1. Warm Up
Find the product.
1. 5 • 5 • 5 • 5
625
2. 3 • 3 • 3 27
3. (–7) • (–7) • (–7)‏
–343
4. 9 • 9 81

2. If a number is in exponential form, the exponent represents how many times the base is to be used as a factor. A number produced by raising a base to an exponent is called a power. Both 27 and 33 represent the same power.
Exponent
Base 7 2

3. Example 1: Writing Exponents
Write in exponential form.
A. 4 • 4 • 4 • 4
B. (–6) • (–6) • (–6)‏ 44
(–6)3
C. 5 • 5 • d • d • d • d
52d4
Read –(63) as “ negative 6 to the 3rd power” or “negative 6 cubed”.
Reading Math

4. Write in exponential form.
Check It Out: Example 1
Write in exponential form.
A. x • x • x • x • x
B. d • d • d x5 d3
C. 7 • 7 • b • b
72b2

5. Example 2: Simplifying Powers
= 3 • 3 • 3 • 3 • 3
= 243
B. (–3)5
= (–3) • (–3) • (–3) • (–3) • (–3)‏
= –243
Helpful Hint
Always use parentheses to raise a negative number to a power.

6. Example 2: Simplifying Powers
C. (–4)4
= (–4) • (–4) • (–4) • (–4)‏
= 256 D.

7. Example 3: Order of Operations
Evaluate x(yx – zy) + x for x = 4, y = 2, and z = 3. y
x(yx – zy) + xy
4(24 – 32) + 42
4(16 – 9) + 16
4(7) + 16 44

8. Evaluate z – 7(2x – xy) for x = 5, y = 2, and z = 60.
Check It Out: Example 3
Evaluate z – 7(2x – xy) for x = 5, y = 2, and z = 60.
z – 7(2x – xy)
60 – 7(25 – 52)‏
60 – 7(32 – 25)
60 – 7(7)
60 – 49 11

9. Write in exponential form. 1. n• n • n• n n
Lesson Quiz
Write in exponential form.
1. n• n • n• n 4 n
2. (–8) • (–8) • (–8) • (h)
(–8)3h
3. Evaluate (–4)4
256
4. Evaluate x • z – yx for x = 5, y = 3, and z = 6.
–213
5. A population of bacteria doubles in size every minute. The number of bacteria after 5 minutes is 15  25. How many are there after 5 minutes?
480