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Key equations

Rules of Exponents
For nonzero real numbers a and b and integers m and n
Product rule a m a n = a m + n
Quotient rule a m a n = a m n
Power rule ( a m ) n = a m n
Zero exponent rule a 0 = 1
Negative rule a n = 1 a n
Power of a product rule ( a b ) n = a n b n
Power of a quotient rule ( a b ) n = a n b n

Key concepts

  • Products of exponential expressions with the same base can be simplified by adding exponents. See [link] .
  • Quotients of exponential expressions with the same base can be simplified by subtracting exponents. See [link] .
  • Powers of exponential expressions with the same base can be simplified by multiplying exponents. See [link] .
  • An expression with exponent zero is defined as 1. See [link] .
  • An expression with a negative exponent is defined as a reciprocal. See [link] and [link] .
  • The power of a product of factors is the same as the product of the powers of the same factors. See [link] .
  • The power of a quotient of factors is the same as the quotient of the powers of the same factors. See [link] .
  • The rules for exponential expressions can be combined to simplify more complicated expressions. See [link] .
  • Scientific notation uses powers of 10 to simplify very large or very small numbers. See [link] and [link] .
  • Scientific notation may be used to simplify calculations with very large or very small numbers. See [link] and [link] .

Section exercises

Verbal

Is 2 3 the same as 3 2 ? Explain.

No, the two expressions are not the same. An exponent tells how many times you multiply the base. So 2 3 is the same as 2 × 2 × 2 , which is 8. 3 2 is the same as 3 × 3 , which is 9.

When can you add two exponents?

What is the purpose of scientific notation?

It is a method of writing very small and very large numbers.

Explain what a negative exponent does.

Numeric

For the following exercises, simplify the given expression. Write answers with positive exponents.

9 2

81

15 −2

3 2 × 3 3

243

4 4 ÷ 4

( 2 2 ) −2

1 16

( 5 8 ) 0

11 3 ÷ 11 4

1 11

6 5 × 6 −7

( 8 0 ) 2

1

5 −2 ÷ 5 2

For the following exercises, write each expression with a single base. Do not simplify further. Write answers with positive exponents.

4 2 × 4 3 ÷ 4 −4

4 9

6 12 6 9

( 12 3 × 12 ) 10

12 40

10 6 ÷ ( 10 10 ) −2

7 −6 × 7 −3

1 7 9

( 3 3 ÷ 3 4 ) 5

For the following exercises, express the decimal in scientific notation.

0.0000314

3.14 × 10 5

148,000,000

For the following exercises, convert each number in scientific notation to standard notation.

1.6 × 10 10

16,000,000,000

9.8 × 10 −9

Algebraic

For the following exercises, simplify the given expression. Write answers with positive exponents.

a 3 a 2 a

a 4

m n 2 m −2

( b 3 c 4 ) 2

b 6 c 8

( x −3 y 2 ) −5

a b 2 ÷ d −3

a b 2 d 3

( w 0 x 5 ) −1

m 4 n 0

m 4

y −4 ( y 2 ) 2

p −4 q 2 p 2 q −3

q 5 p 6

( l × w ) 2

( y 7 ) 3 ÷ x 14

y 21 x 14

( a 2 3 ) 2

5 2 m ÷ 5 0 m

25

( 16 x ) 2 y −1

2 3 ( 3 a ) −2

72 a 2

( m a 6 ) 2 1 m 3 a 2

( b −3 c ) 3

c 3 b 9

( x 2 y 13 ÷ y 0 ) 2

( 9 z 3 ) −2 y

y 81 z 6

Real-world applications

To reach escape velocity, a rocket must travel at the rate of 2.2 × 10 6 ft/min. Rewrite the rate in standard notation.

A dime is the thinnest coin in U.S. currency. A dime’s thickness measures 1.35 × 10 −3 m. Rewrite the number in standard notation.

0.00135 m

The average distance between Earth and the Sun is 92,960,000 mi. Rewrite the distance using scientific notation.

A terabyte is made of approximately 1,099,500,000,000 bytes. Rewrite in scientific notation.

1.0995 × 10 12

The Gross Domestic Product (GDP) for the United States in the first quarter of 2014 was $ 1.71496 × 10 13 . Rewrite the GDP in standard notation.

One picometer is approximately 3.397 × 10 −11 in. Rewrite this length using standard notation.

0.00000000003397 in.

The value of the services sector of the U.S. economy in the first quarter of 2012 was $10,633.6 billion. Rewrite this amount in scientific notation.

Technology

For the following exercises, use a graphing calculator to simplify. Round the answers to the nearest hundredth.

( 12 3 m 33 4 −3 ) 2

12,230,590,464 m 66

17 3 ÷ 15 2 x 3

Extensions

For the following exercises, simplify the given expression. Write answers with positive exponents.

( 3 2 a 3 ) −2 ( a 4 2 2 ) 2

a 14 1296

( 6 2 −24 ) 2 ÷ ( x y ) −5

m 2 n 3 a 2 c −3 a −7 n −2 m 2 c 4

n a 9 c

( x 6 y 3 x 3 y −3 y −7 x −3 ) 10

( ( a b 2 c ) −3 b −3 ) 2

1 a 6 b 6 c 6

Avogadro’s constant is used to calculate the number of particles in a mole. A mole is a basic unit in chemistry to measure the amount of a substance. The constant is 6.0221413 × 10 23 . Write Avogadro’s constant in standard notation.

Planck’s constant is an important unit of measure in quantum physics. It describes the relationship between energy and frequency. The constant is written as 6.62606957 × 10 −34 . Write Planck’s constant in standard notation.

0.000000000000000000000000000000000662606957

Practice Key Terms 1

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Source:  OpenStax, Selected topics in algebra. OpenStax CNX. Sep 02, 2015 Download for free at http://legacy.cnx.org/content/col11877/1.2
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