Evaluating Expressions

1
Evaluating Expressions

• Deborah Smith

2
To evaluate a variable expression, you first
replace each variable with a number.

• Evaluate 4y 15 for y 9.
• 4(9) 15
• 36 15
• 21

3
Evaluate.

• 63 5x for x 7
• 63 5(7)
• 63 35
• 28

4
Evaluate.

• 4 (t 3) for t 8
• 4 (83)
• 4 (11)
• 44

5
Replacing more than one variable.

• 3ab c/2 for a 2, b 5, c 10
• 3(2)(5) 10/2
• 30 5
• 35

6
Evaluate.

• 6(g h) g 8, h 7
• 6(87)
• 6(15)
• 90

7
Evaluate.

• 2xy z for x4, y3, z1
• 2(4)(3) 1
• 24 1
• 23

8
Evaluate.

• r s r13, s11
• 2
• 13 11 24
• 24/2
• 12

9
Energy drinks come in cases of 24 bottles.

• Write and evaluate a variable expression for the
  number of cases a store should order to get b
  bottles of energy drinks.
• b/24
• Evaluate the expression for 120 bottles.
• 5 cases

10
The store pays 29 for each case of energy drinks.

• Write a variable expression for the cost of c
  cases.
• 29c
• Evaluate the expression for the cost of 5 cases.
• 145

11
An online music store charges 14 for each CD.
Shipping is 6 per order.

• Write a variable expression for the cost of
  ordering CDs.
• 14n 6
• Evaluate the expression for the cost of 4 CDs.
• 62

12
An online music store charges 14 for each CD.
Shipping is 6 per order.

• Write a variable expression for the cost of
  ordering CDs.
• 14n 6
• Evaluate the expression for the cost of 7 CDs.
• 104