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x 5 x 2 = x x x x x x x = ( x x ) x x x ( x x ) = x x x = x 3 . Notice that 5 2 = 3 .

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a 8 a 3 = a a a a a a a a a a a = ( a a a ) a a a a a ( a a a ) = a a a a a = a 5 . Notice that 8 3 = 5 .

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Quotient rule for exponents

If x is a real number and n and m are natural numbers,

x n x m = x n m , x 0 .

To divide two exponential quantities having the same nonzero base, subtract the exponent of the denominator from the exponent of the numerator. Keep in mind that the exponential quantities being divided must have the same base for this rule to apply.

Sample set c

Find the following quotients. All exponents are natural numbers.

x 5 x 2 = x 5-2 = x 3 The part in the box is usally done mentally .

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27 a 3 b 6 c 2 3 a 2 b c = 9 a 3 2 b 6 1 c 2 1 = 9 a b 5 c

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15 x 3 x = 5 x

The bases are the same, so we subtract the exponents. Although we don’t know exactly what is, the notation indicates the subtraction.

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Practice set c

Find each quotient

( x + 6 ) 5 ( x + 6 ) 3

( x + 6 ) 2

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26 x 4 y 6 z 2 13 x 2 y 2 z

2 x 2 y 4 z

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When we make the subtraction, n m , in the division x n x m , there are three possibilities for the values of the exponents:

  1. The exponent of the numerator is greater than the exponent of the denominator, that is, n > m . Thus, the exponent, n m , is a natural number.
  2. The exponents are the same, that is, n = m . Thus, the exponent, n m , is zero, a whole number.
  3. The exponent of the denominator is greater than the exponent of the numerator, that is, n < m . Thus, the exponent, n m , is an integer.

Zero as an exponent

In Sample Set C, the exponents of the numerators were greater than the exponents of the denominators. Let’s study the case when the exponents are the same.

When the exponents are the same, say n , the subtraction n n produces 0.

Thus, by the second rule of exponents, x n x n = x n n = x 0 .

But what real number, if any, does x 0 represent? Let’s think for a moment about our experience with division in arithmetic. We know that any nonzero number divided by itself is one.

8 8 = 1 , 43 43 = 1 , 258 258 = 1

Since the letter x represents some nonzero real number, so does x n . Thus, x n x n

represents some nonzero real number divided by itself. Then x n x n = 1 .

But we have also established that if x 0 , x n x n = x 0 . We now have that x n x n = x 0

and x n x n = 1 . This implies that x 0 = 1 , x 0 .

Exponents can now be natural numbers and zero. We have enlarged our collection of numbers that can be used as exponents from the collection of natural numbers to the collection of whole numbers.

Zero as an exponent

If x 0 , x 0 = 1

Any number, other than 0, raised to the power of 0, is 1. 0 0 has no meaning (it does not represent a number).

Sample set d

Find each value. Assume the base is not zero.

2 x 2 x 2 = 2 x 0 = 2 1 = 2

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5 ( x + 4 ) 8 ( x 1 ) 5 5 ( x + 4 ) 3 ( x 1 ) 5 = ( x + 4 ) 8 3 ( x 1 ) 5 5 = ( x + 4 ) 5 ( x 1 ) 0 = ( x + 4 ) 5

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Practice set d

Find each value. Assume the base is not zero.

6 x 4 2 x 3

3 x 4 3 = 3 x

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14 a 7 7 a 2

2 a 7 2 = 2 a 5

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26 x 2 y 5 4 x y 2

13 2 x y 3

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36 a 4 b 3 c 8 8 a b 3 c 6

9 2 a 3 c 2

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51 ( a 4 ) 3 17 ( a 4 )

3 ( a 4 ) 2

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52 a 7 b 3 ( a + b ) 8 26 a 2 b ( a + b ) 8

2 a 5 b 2

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14 x r y p z q 2 x r y h z 5

7 y p h z q 5

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We will study the case where the exponent of the denominator is greater than the exponent of the numerator in Section [link] .

Exercises

Use the product rule and quotient rule of exponents to simplify the following problems. Assume that all bases are nonzero and that all exponents are whole numbers.

12 x y 3 z 2 4 x 2 y 2 z 3 x

144 x 4 y 5 z 3

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( 4 x 2 ) ( 8 x y 3 )

32 x 3 y 3

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( 2 x y ) ( 3 y ) ( 4 x 2 y 5 )

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( 1 4 a 2 b 4 ) ( 1 2 b 4 )

1 8 a 2 b 8

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( 3 8 ) ( 16 21 x 2 y 3 ) ( x 3 y 2 )

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15 x 20 y 24 z 4 5 x 19 y z

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24 x 4 y 4 z 0 w 8 9 x y w 7

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a 4 b 6 ( a 10 b 16 a 5 b 7 )

a 9 b 15

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3 a 2 b 3 ( 14 a 2 b 5 2 b )

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( x + 3 y ) 11 ( 2 x 1 ) 4 ( x + 3 y ) 3 ( 2 x 1 )

( x + 3 y ) 8 ( 2 x 1 ) 3

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40 x 5 z 10 ( z x 4 ) 12 ( x + z ) 2 10 z 7 ( z x 4 ) 5

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x n x n + 3

x 2 n + 3

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a Δ a b b

a Δ + b +

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Exercises for review

( [link] ) What natural numbers can replace x so that the statement 5 < x 3 is true?

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( [link] ) Use the distributive property to expand 4 x ( 2 a + 3 b ) .

8 a x + 12 b x

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( [link] ) Express x x x y y y y ( a + b ) ( a + b ) using exponents.

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( [link] ) Find the value of 4 2 + 3 2 2 3 10 8 .

8

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( [link] ) Find the value of 4 2 + ( 3 + 2 ) 2 1 2 3 5 + 2 4 ( 3 2 2 3 ) 4 2 .

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Questions & Answers

how did you get 1640
Noor Reply
If auger is pair are the roots of equation x2+5x-3=0
Peter Reply
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
MATTHEW Reply
420
Sharon
from theory: distance [miles] = speed [mph] × time [hours] info #1 speed_Dennis × 1.5 = speed_Wayne × 2 => speed_Wayne = 0.75 × speed_Dennis (i) info #2 speed_Dennis = speed_Wayne + 7 [mph] (ii) use (i) in (ii) => [...] speed_Dennis = 28 mph speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5. Substituting the first equation into the second: W * 2 = (W + 7) * 1.5 W * 2 = W * 1.5 + 7 * 1.5 0.5 * W = 7 * 1.5 W = 7 * 3 or 21 W is 21 D = W + 7 D = 21 + 7 D = 28
Salma
Devon is 32 32​​ years older than his son, Milan. The sum of both their ages is 54 54​. Using the variables d d​ and m m​ to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
Aaron Reply
find product (-6m+6) ( 3m²+4m-3)
SIMRAN Reply
-42m²+60m-18
Salma
what is the solution
bill
how did you arrive at this answer?
bill
-24m+3+3mÁ^2
Susan
i really want to learn
Amira
I only got 42 the rest i don't know how to solve it. Please i need help from anyone to help me improve my solving mathematics please
Amira
Hw did u arrive to this answer.
Aphelele
hi
Bajemah
-6m(3mA²+4m-3)+6(3mA²+4m-3) =-18m²A²-24m²+18m+18mA²+24m-18 Rearrange like items -18m²A²-24m²+42m+18A²-18
Salma
complete the table of valuesfor each given equatio then graph. 1.x+2y=3
Jovelyn Reply
x=3-2y
Salma
y=x+3/2
Salma
Hi
Enock
given that (7x-5):(2+4x)=8:7find the value of x
Nandala
3x-12y=18
Kelvin
please why isn't that the 0is in ten thousand place
Grace Reply
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
Marry Reply
how far
Abubakar
cool u
Enock
state in which quadrant or on which axis each of the following angles given measure. in standard position would lie 89°
Abegail Reply
hello
BenJay
hi
Method
I am eliacin, I need your help in maths
Rood
how can I help
Sir
hmm can we speak here?
Amoon
however, may I ask you some questions about Algarba?
Amoon
hi
Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
cameron Reply
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
mahnoor Reply
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67. Check: Sales = 3542 Commission 12%=425.04 Pay = 500 + 425.04 = 925.04. 925.04 > 925.00
Munster
difference between rational and irrational numbers
Arundhati Reply
When traveling to Great Britain, Bethany exchanged $602 US dollars into £515 British pounds. How many pounds did she receive for each US dollar?
Jakoiya Reply
how to reduced echelon form
Solomon Reply
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?
Zack Reply
d=r×t the equation would be 8/r+24/r+4=3 worked out
Sheirtina
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Source:  OpenStax, Elementary algebra. OpenStax CNX. May 08, 2009 Download for free at http://cnx.org/content/col10614/1.3
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