Information about 2.2 variables, evaluation and expressions w

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them.

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures.

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2,

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2, then “2*x” or “2x” is the expression for the cost of x apples.

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2, then “2*x” or “2x” is the expression for the cost of x apples. So if we have 6 apples,

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2, then “2*x” or “2x” is the expression for the cost of x apples. So if we have 6 apples, by setting the x as (6) in the expression 2x, we obtain 2(6) = $12 for the cost of 6 apples.

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2, then “2*x” or “2x” is the expression for the cost of x apples. So if we have 6 apples, by setting the x as (6) in the expression 2x, we obtain 2(6) = $12 for the cost of 6 apples. The value “6” for x is called the input (value). the input x = 6:

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2, then “2*x” or “2x” is the expression for the cost of x apples. So if we have 6 apples, by setting the x as (6) in the expression 2x, we obtain 2(6) = $12 for the cost of 6 apples. The value “6” for x is called the input (value). The answer “$12” is called the output (value). the input x = 6: the output : 2(6) = $12

Variables, Evaluation and Linear Expressions In mathematics we use symbols such as x, y and z to represent numbers.These symbols are called variables because their values change according to the values assigned to them. We use numbers, variables and mathematics operations to form (variable)-expressions to describe calculation procedures. For example, if x represents the number of apples and each apple cost $2, then “2*x” or “2x” is the expression for the cost of x apples. So if we have 6 apples, by setting the x as (6) in the expression 2x, we obtain 2(6) = $12 for the cost of 6 apples. The value “6” for x is called the input (value). The answer “$12” is called the output (value). the input x = 6: the output : 2(6) = $12 The above process of replacing the variable(s) with input value(s) to find the output is called evaluation.

Variables, Evaluation and Linear Expressions Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 b. 5 + 3y with y = 2 c. 5z2 with z = 3

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 b. 5 + 3y with y = 2 c. 5z2 with z = 3

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 3+x replace x by (5) b. 5 + 3y with y = 2 c. 5z2 with z = 3

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) 3+x replace x by (5) b. 5 + 3y with y = 2 c. 5z2 with z = 3

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x by (5) b. 5 + 3y with y = 2 c. 5z2 with z = 3

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 c. 5z2 with z = 3

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 5 + 3y c. 5z2 with z = 3 replace y by (2)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) c. 5z2 with z = 3 5 + 3y replace y by (2)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) = 5 + 6 = 11. c. 5z2 with z = 3 5 + 3y replace y by (2)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) = 5 + 6 = 11. The input is y = 2 and the output is 11. c. 5z2 with z = 3 5 + 3y replace y by (2)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) = 5 + 6 = 11. The input is y = 2 and the output is 11. 5 + 3y replace y by (2) c. 5z2 with z = 3 5z2 replace z by (3)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) = 5 + 6 = 11. The input is y = 2 and the output is 11. c. 5z2 with z = 3 Set z = 3 we’ve 5(3)2 5 + 3y 5z2 replace y by (2) replace z by (3)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) = 5 + 6 = 11. The input is y = 2 and the output is 11. c. 5z2 with z = 3 Set z = 3 we’ve 5(3)2 = 5 * 9 = 45 5 + 3y 5z2 replace y by (2) replace z by (3)

Variables, Evaluation and Linear Expressions To evaluate an expression, replace the variable(s) with the assigned input-value(s) enclosed by ( )’s, then compute the resulting expression following the rules of order of operations. Example A. Evaluate the following expressions with the given input values. Specify the input and the output. a. 3 + x with x = 5 Set x = 5 we’ve 3 + x = 3 + (5) = 8. 3+x replace x The input is x = 5 and the output is 8. by (5) b. 5 + 3y with y = 2 Set y = 2 we’ve 5 + 3(2) = 5 + 6 = 11. The input is y = 2 and the output is 11. 5 + 3y c. 5z2 with z = 3 Set z = 3 we’ve 5(3)2 = 5 * 9 = 45 The input is z = 3 and the output is 45. 5z2 replace y by (2) replace z by (3)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 5 + 3(20 – 3z2) replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) = 5 + 3(20 – 3*4) 5 + 3(20 – 3z2) replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) = 5 + 3(20 – 3*4) = 5 + 3(20 – 12) 5 + 3(20 – 3z2) replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) = 5 + 3(20 – 3*4) = 5 + 3(20 – 12) = 5 + 3(8) 5 + 3(20 – 3z2) replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) = 5 + 3(20 – 3*4) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 5 + 3(20 – 3z2) replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) = 5 + 3(20 – 3*4) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. replace z by (2)

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z = 5 + 3(20 – 3*4) by (2) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. The word “evaluation” here does not mean “to judge” as in “student-evaluation”.

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z = 5 + 3(20 – 3*4) by (2) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. The word “evaluation” here does not mean “to judge” as in “student-evaluation”. In mathematics, “evaluation” is the forward-computation where we plug in the known quantities in a formula to obtain the corresponding output.

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z = 5 + 3(20 – 3*4) by (2) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. The word “evaluation” here does not mean “to judge” as in “student-evaluation”. In mathematics, “evaluation” is the forward-computation where we plug in the known quantities in a formula to obtain the corresponding output. Linear Expressions

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z = 5 + 3(20 – 3*4) by (2) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. The word “evaluation” here does not mean “to judge” as in “student-evaluation”. In mathematics, “evaluation” is the forward-computation where we plug in the known quantities in a formula to obtain the corresponding output. Linear Expressions In life, we often need to compute in the following manner:

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z = 5 + 3(20 – 3*4) by (2) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. The word “evaluation” here does not mean “to judge” as in “student-evaluation”. In mathematics, “evaluation” is the forward-computation where we plug in the known quantities in a formula to obtain the corresponding output. Linear Expressions In life, we often need to compute in the following manner: * perform a multiplication/division to obtain a product/quotient,

Variables, Evaluation and Linear Expressions d. 5 + 3(20 – 3z2) with z = 2 Set z = 2 we’ve 5 + 3(20 – 3(2)2) 5 + 3(20 – 3z2) replace z = 5 + 3(20 – 3*4) by (2) = 5 + 3(20 – 12) = 5 + 3(8) = 5 + 24 = 29 The input is z = 2 and the output is 29. The word “evaluation” here does not mean “to judge” as in “student-evaluation”. In mathematics, “evaluation” is the forward-computation where we plug in the known quantities in a formula to obtain the corresponding output. Linear Expressions In life, we often need to compute in the following manner: * perform a multiplication/division to obtain a product/quotient, * then add/subtract another number with the above result.

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order?

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 =

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67.

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s.

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 =

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 = 90 + 7 = $97. So the total cost for the order is $97 for 9 DVD’s.

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 = 90 + 7 = $97. So the total cost for the order is $97 for 9 DVD’s. c. Describe the input and output variables and what are the specific input and the output for each problem?

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 = 90 + 7 = $97. So the total cost for the order is $97 for 9 DVD’s. c. Describe the input and output variables and what are the specific input and the output for each problem? The input variable is “the number of DVD’s ordered”.

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 = 90 + 7 = $97. So the total cost for the order is $97 for 9 DVD’s. c. Describe the input and output variables and what are the specific input and the output for each problem? The input variable is “the number of DVD’s ordered”. The output variable is “the total cost”.

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 = 90 + 7 = $97. So the total cost for the order is $97 for 9 DVD’s. c. Describe the input and output variables and what are the specific input and the output for each problem? The input variable is “the number of DVD’s ordered”. The output variable is “the total cost”. Let’s name “the number of DVD’s ordered” as x, then for the input x = 6, the output is $67,

Variables, Evaluation and Linear Expressions Example B. a. An online order sells DVD’s for $10/disc with a $7 shipping and handling fee for each order. We ordered 6 DVD’s, how much is the total cost for the order? Calculate the cost of the 6 DVD’s, then add the $7 handling fee: 10(6) + 7 = 60 + 7 = $67. So the total cost for the order is $67 for 6 DVD’s. b. We change the order to 9 DVD’s, how much is the total cost? Multiply, then add: 10(9) + 7 = 90 + 7 = $97. So the total cost for the order is $97 for 9 DVD’s. c. Describe the input and output variables and what are the specific input and the output for each problem? The input variable is “the number of DVD’s ordered”. The output variable is “the total cost”. Let’s name “the number of DVD’s ordered” as x, then for the input x = 6, the output is $67, and for the input x = 9, the output is $97.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered,

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x,

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7. Example C. We have a filled 1,000-gallon water tank. On the average, we use 15 gallons of water each day. How much water is left in the tank after 10 days? How about after 1 month, i.e. 30 days? Write down the expression that calculates the amount of water left after x days.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7. Example C. We have a filled 1,000-gallon water tank. On the average, we use 15 gallons of water each day. How much water is left in the tank after 10 days? How about after 1 month, i.e. 30 days? Write down the expression that calculates the amount of water left after x days. After 10 days, we used 15(10) = 150 gallons of water.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7. Example C. We have a filled 1,000-gallon water tank. On the average, we use 15 gallons of water each day. How much water is left in the tank after 10 days? How about after 1 month, i.e. 30 days? Write down the expression that calculates the amount of water left after x days. After 10 days, we used 15(10) = 150 gallons of water. So there is 1,000 – 150 = 850 gallons left.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7. Example C. We have a filled 1,000-gallon water tank. On the average, we use 15 gallons of water each day. How much water is left in the tank after 10 days? How about after 1 month, i.e. 30 days? Write down the expression that calculates the amount of water left after x days. After 10 days, we used 15(10) = 150 gallons of water. So there is 1,000 – 150 = 850 gallons left. After 30 days, we used 15(30) = 450 gallons of water.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7. Example C. We have a filled 1,000-gallon water tank. On the average, we use 15 gallons of water each day. How much water is left in the tank after 10 days? How about after 1 month, i.e. 30 days? Write down the expression that calculates the amount of water left after x days. After 10 days, we used 15(10) = 150 gallons of water. So there is 1,000 – 150 = 850 gallons left. After 30 days, we used 15(30) = 450 gallons of water. So there is 1,000 – 1450 = 550 gallons left.

Variables, Evaluation and Linear Expressions d. Write the expression for calculating the total cost of an order using the variable “x” where x = the number of DVD’s ordered, The cost of the x DVD’s is 10x, adding the $7 handling fee, we have the expression for the total cost to be 10x + 7. Example C. We have a filled 1,000-gallon water tank. On the average, we use 15 gallons of water each day. How much water is left in the tank after 10 days? How about after 1 month, i.e. 30 days? Write down the expression that calculates the amount of water left after x days. After 10 days, we used 15(10) = 150 gallons of water. So there is 1,000 – 150 = 850 gallons left. After 30 days, we used 15(30) = 450 gallons of water. So there is 1,000 – 1450 = 550 gallons left. After x days, we used 15(x) = 15x gallons of water. So there is 1,000 – 15x gallons left.

Variables, Evaluation and Linear Expressions Linear Expressions Expressions of the form ax + b, where a and b are constants, i.e. fixed numbers like the $10/DVD and $7 fee in the last example, with x as the variable, are called linear expressions.

Variables, Evaluation and Linear Expressions Linear Expressions Expressions of the form ax + b, where a and b are constants, i.e. fixed numbers like the $10/DVD and $7 fee in the last example, with x as the variable, are called linear expressions. Linear expressions do not involve x2, x3, etc.. or division by x so expressions such as 3x2 + 1 or 12 ÷ x are non-linear.

Variables, Evaluation and Linear Expressions Linear Expressions Expressions of the form ax + b, where a and b are constants, i.e. fixed numbers like the $10/DVD and $7 fee in the last example, with x as the variable, are called linear expressions. Linear expressions do not involve x2, x3, etc.. or division by x so expressions such as 3x2 + 1 or 12 ÷ x are non-linear. Linear expressions arise frequently in everyday computation. Because linear expressions are easy to compute, they also are utilized to estimate more complicated non-linear expressions.

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Evaluation: Evaluating ... plug and chug" aspect of evaluation: plugging in values for variables, and ... "Evaluation: Evaluating Expressions, ...

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©P q2s0 31z2F oK lu Qt0a P MSTo rfFt xwra TrGez jLPLiC o.x F 4A dlYl H GrJirgAhAtPsu LrPe8swe3r1v LeQd5. p W ... Expressions Date ... 2 2 19) x 3 ÷ 3 ...

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3.2 Evaluating Algebraic Expressions ... x2 −2xy +y2 Original expression. = ( −3)2 −2( −3)( 2)+ ... all occurrences of variables in the expression ...

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Variables and Expressions 20. ... How do you evaluate the expression 3 1 4 3 2 2 10 4 5? ... 7w2 2 14w2 30. 6a 2 7 1 4 2 a

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... equations and functions / Expressions and variables / Expressions and variables. ... An expression that represents repeated multiplication of the same ...

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Tutorial 4: Introduction to Variable Expressions and Equations. ... So if we let the length be the variable l and width be w ...

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Multiple Choice Practice - Variables and Expressions ... 4x 2 [2] 15; 4x 2 [3] 15; -2x 2 [4] -15; -2x 2 . 13. (x + 4) 2 = [1] x 2 + 16 ...

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