1. 1. Simplify (– 3x)2.
ANSWER
9x2
2. Simplify a3 2b 5
ANSWER
a15
32b5

2. 3. The order of magnitude of Earth’s mass is about 1027 grams
3. The order of magnitude of Earth’s mass is about 1027 grams. The order of magnitude of the sun’s mass is about 1033 grams. About how many times as great is the sun’s mass as Earth’s mass?
ANSWER
about 106

3. Use definition of zero and negative exponents
EXAMPLE 1
Use definition of zero and negative exponents 1 32 =
a. 3– 2
Definition of negative exponents 1 9 =
Evaluate power.
b. (–7)0
= 1
Definition of zero exponent

4. Use definition of zero and negative exponents
EXAMPLE 1
Use definition of zero and negative exponents 5 –2 1 c. = 1 5 2
Definition of negative exponents 1 25 =
Evaluate power.
= 25
Simplify by multiplying numerator
and denominator by 25. 1
0 5
(Undefined) =
d – 5
a – n is defined only for a nonzero
number a.

5. GUIDED PRACTICE
for Example 1
Evaluate the expression. 2 3 1. 1 2 3. –3 = 1
= 8
2. (–8) – 2 1 64 =
4. (–1 )0
= 1

6. Evaluate exponential expressions
EXAMPLE 2
Evaluate exponential expressions
a. 6–
= 6– 4 + 4
Product of a power property
= 60
Add exponents.
= 1
Definition of zero exponent

7. Evaluate exponential expressions
EXAMPLE 2
Evaluate exponential expressions
b. (4– 2)2
= 4– 2 ∙ 2
Power of a power property
= 4– 4
Multiply exponents. 1 4 =
Definition of negative exponents 1
256 =
Evaluate power. c. 1
3– 4
= 34
Definition of negative exponents
= 81
Evaluate power.

8. Evaluate exponential expressions
EXAMPLE 2
Evaluate exponential expressions d.
5– 1 52
= 5– 1 – 2
Quotient of powers property
= 5– 3
Subtract exponents. 1 53 =
Definition of negative exponents 1
125 =
Evaluate power.

9. GUIDED PRACTICE
for Example 2
Evaluate the expression. 5. 1
4– 3
= 64
7. (– 3 )
(– 3 ) – 5 5
= 1 8.
6– 2 62 1
1296 =
6. (5– 3) – 1
= 125

10. Use properties of exponents
EXAMPLE 3
Use properties of exponents
Simplify the expression. Write your answer using only positive exponents.
a. (2xy–5)3
= 23 x3 (y–5)3
Power of a product property
= 8 x3 y–15
Power of a power property =
y15
8x3
Definition of negative exponents

11. Use properties of exponents
EXAMPLE 3
Use properties of exponents
(2x)–2y5
–4x2y2 b. y5
(2x)2(–4x2y2) =
Definition of negative exponents y5
(4x2)(–4x2y2) =
Power of a product property y5
–16x4y2 =
Product of powers property y3
16x4 – =
Quotient of powers property

12. EXAMPLE 4
Standardized Test Practice
The order of magnitude of the mass of a polyphemus moth larva when it hatches is 10-3 gram. During the first 56 days of its life, the moth larva can eat about 105 times its own mass in food. About how many grams of food can the moth larva eat during its first 56 days? A
10–15 gram B
gram C
100 grams D
10,000,000 grams

13. EXAMPLE 4
Standardized Test Practice
SOLUTION
To find the amount of food the moth larva can eat in the first 56 days of its life, multiply its original mass, 10– 3, by 105. –3
= (–3)
= 102
= 100
The moth larva can eat about 100 grams of food in the first 56 days of its life.
ANSWER
The correct answer is C. A B C D

14. GUIDED PRACTICE
for Examples 3 and 4
9x3y
3xy – 3
9. Simplify the expression Write your answer
using only positive exponents. 1
3x2y4
ANSWER
10. SCIENCE The order of magnitude of the mass of a proton is 104 times greater than the order of magnitude of the mass of an electron, which is 10–27 gram. Find the order of magnitude of the mass of a proton.
ANSWER
10 –23 g

15. Daily Homework Quiz
1. Evaluate 5 2
– 3
ANSWER 8
125 4 –7 3
2. Evaluate
ANSWER 1
256
3. Simplify 6a –4 b .
ANSWER 6 a 4

16. Daily Homework Quiz
4. Simplify
8x3y –4
12x2y –3 .
ANSWER 2x 3y
A human cell uses on average about 10–12 watts of power. The laser in a CD-R drive uses times as many watts. About how many watts of power does the laser in a CD-R drive use? 5.
ANSWER
About 10–3