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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

Ayele, K., 2003. Introductory Economics, 3rd ed., Addis Ababa.
Widad Reply
can you send the book attached ?
Ariel
?
Ariel
What is economics
Widad Reply
the study of how humans make choices under conditions of scarcity
AI-Robot
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn Reply
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn
what is ecnomics
Jan Reply
this is the study of how the society manages it's scarce resources
Belonwu
what is macroeconomic
John Reply
macroeconomic is the branch of economics which studies actions, scale, activities and behaviour of the aggregate economy as a whole.
husaini
etc
husaini
difference between firm and industry
husaini Reply
what's the difference between a firm and an industry
Abdul
firm is the unit which transform inputs to output where as industry contain combination of firms with similar production 😅😅
Abdulraufu
Suppose the demand function that a firm faces shifted from Qd  120 3P to Qd  90  3P and the supply function has shifted from QS  20  2P to QS 10  2P . a) Find the effect of this change on price and quantity. b) Which of the changes in demand and supply is higher?
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Jan
economics is a science that studies human behaviour as a relationship b/w ends and scares means which have alternative uses
Jan
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Nomsa Reply
out-of-pocket costs for a firm, for example, payments for wages and salaries, rent, or materials
AI-Robot
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economic overview notes
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identify a demand and a supply curve
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i don't know
Parul
there's a difference
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Demand curve shows that how supply and others conditions affect on demand of a particular thing and what percent demand increase whith increase of supply of goods
Israr
Hi Sir please how do u calculate Cross elastic demand and income elastic demand?
Abari
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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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