1. Evaluate Expressions
Warm Up
Lesson Presentation
Lesson Quiz

2. Warm-Up
Perform the indicated operation.
ANSWER 8
ANSWER
23.1

3. Perform the indicated operation.
Warm-Up
Perform the indicated operation.
– 5.9
ANSWER
5.7
4. Julia ran miles last week and miles this week.
How many more miles did she run last week? 2 3 5 6
ANSWER
1 mi 5 6

4. Evaluate the expression when n = 3.
Example 1
Evaluate the expression when n = 3.
a n =
13 3
Substitute 3 for n.
= 39
Multiply. b. 9 n 9 3 =
Substitute 3 for n.
= 3
Divide.
c. n – 1 =
3 – 1
Substitute 3 for n.
= 2
Subtract.
d. n =
3 + 8
Substitute 3 for n.
= 11
Add.

5. Guided Practice
Evaluate the expression when y = 2.
ANSWERS
1. 6y
1. 12 2. 8 y
2. 4
3. y + 4
3. 6
– y
4. 9

6. Example 2
Movies
The total cost of seeing a movie at a theater can be represented by the expression a + r where a is the cost (in dollars) of admission and r is the cost (in dollars) of refreshments. Suppose you pay $7.50 for admission and $7.25 for refreshments. Find the total cost.

7. Example 2 SOLUTION Total cost = a + r = 7.50 + 7.25 = 14.75 ANSWER
Write expression. =
Substitute 7.50 for a and
7.25 for r. =
Add.
The total cost is $14.75
ANSWER

8. Guided Practice
WHAT IF? In Example 2, suppose you go back to the theater with a friend to see an afternoon movie. You pay for both admissions.Your total cost (in dollars) can be represented by the expression 2a. If each admission costs $4.75, what is your total cost?
The total cost is $9.50.
ANSWER

9. Example 3
Write the power in words and as a product.
Product
Words
Power a
seven to the first power 7 b
five to the second power,
or five squared
5 5 c.
1 3 2 1 2
one half to the third power, or one half cubed
d. z5
z to the fifth power
z z z z z

10. Guided Practice
Write the power in words and as a product.
Product
Words
Power
Nine to the fifth power
Two to the eighth power 8. n4
n to the fourth power
n n n n

11. Example 4
Evaluate the expression.
a. x4 when x = 2
b. n3 when n = 1.5
SOLUTION
a. x4 = 24
b. n3 = 1.53 =
= (1.5)(1.5)(1.5)
= 16 =

12. Guided Practice
Evaluate the expression.
ANSWERS
9. x3 when x = 8
k3 when k = 2.5
d4 when d = 1 3
11. 1 81

13. The volume of the storage cube is 2744 cubic inches.
Example 5
Storage cubes
Each edge of the medium-sized pop-up storage cube shown is 14 inches long. The storage cube is made so that it can be folded flat when not in use. Find the volume of the storage cube.
SOLUTION
V = s3
Write formula for volume.
= 143
Substitute 14 for s.
= 2744
Evaluate power.
The volume of the storage cube is 2744 cubic inches.

14. Guided Practice
WHAT IF? In Example 5, suppose the storage cube is folded flat to form a square. Find the area of the square.
The area of square is 196 in2.
ANSWER

15. Lesson Quiz
Evaluate the expression or power.
g when g = 7
ANSWER 91
– a when a = 0.75
ANSWER
0.9
ANSWER
625 1 3 4.
ANSWER 1 27

16. Lesson Quiz
Emily is saving for a $300 bicycle. She has saved $ The amount she still needs to save is given by the expression c – s, where c is the cost of the bicycle and s is the amount she has saved. How much does she have left to save? 5.
$171.75
ANSWER