Prealgebra 2e — Original English

Divide Monomials

Simplify Expressions Using the Quotient Property of Exponents

Earlier in this chapter, we developed the properties of exponents for multiplication. We summarize these properties here.

Now we will look at the exponent properties for division. A quick memory refresher may help before we get started. In Fractions you learned that fractions may be simplified by dividing out common factors from the numerator and denominator using the Equivalent Fractions Property. This property will also help us work with algebraic fractions—which are also quotients.

As before, we'll try to discover a property by looking at some examples.

Considerx5x2andx2x3What do they mean?xxxxxxxxxxxxUse the Equivalent Fractions Property.xxxxxxx1xx1xxxSimplify.x31x

Notice that in each case the bases were the same and we subtracted the exponents.

  • When the larger exponent was in the numerator, we were left with factors in the numerator and 1 in the denominator, which we simplified.
  • When the larger exponent was in the denominator, we were left with factors in the denominator, and 1 in the numerator, which could not be simplified.

We write:

x5x2x2x3x521x32x31x

A couple of examples with numbers may help to verify this property.

3432=?3425253=?1532819=?3225125=?1519=915=15

When we work with numbers and the exponent is less than or equal to 3, we will apply the exponent. When the exponent is greater than 3, we leave the answer in exponential form.

Simplify:
  1. x10x8
  2. 2922
Solution

Solution

To simplify an expression with a quotient, we need to first compare the exponents in the numerator and denominator.

Since 10 > 8, there are more factors of x in the numerator. x10x8
Use the quotient property with m>n,aman=amn. The mathematical expression x^(10-8) is displayed, with the exponent '10-8' rendered in red atop a black 'x' on a white background.
Simplify. x2
Since 9 > 2, there are more factors of 2 in the numerator. 2922
Use the quotient property with m>n,aman=amn. A mathematical expression showing the number 2 raised to the power of 9 minus 2 (2^(9-2)).
Simplify. 27

Notice that when the larger exponent is in the numerator, we are left with factors in the numerator.

Simplify:
  1. b10b15
  2. 3335
Solution

Solution

To simplify an expression with a quotient, we need to first compare the exponents in the numerator and denominator.

Since 15 > 10, there are more factors of b in the denominator. b10b15
Use the quotient property with n>m,aman=1anm. A mathematical expression showing the fraction 1 over b raised to the power of 15 minus 10.
Simplify. 1b5
Since 5 > 3, there are more factors of 3 in the denominator. 3335
Use the quotient property with n>m,aman=1anm. The fraction 1 over 3 raised to the power of (5-3). The numerator '1' and the exponent '5-3' are red, with the base '3' in black.
Simplify. 132
Apply the exponent. 19

Notice that when the larger exponent is in the denominator, we are left with factors in the denominator and 1 in the numerator.

Simplify:
  1. a5a9
  2. x11x7
Solution

Solution

Since 9 > 5, there are more a's in the denominator and so we will end up with factors in the denominator. a5a9
Use the Quotient Property for n>m,aman=1anm. The fraction 1 over 'a' raised to the power of (9 minus 5). The numerator '1' and the exponent '9-5' are highlighted in red, contrasting with the black 'a' and fraction bar.
Simplify. 1a4
Notice there are more factors of x in the numerator, since 11 > 7. So we will end up with factors in the numerator. x11x7
Use the Quotient Property for m>n,aman=anm. A mathematical expression showing 'x' raised to the power of '11-7', with the exponent in red color.
Simplify. x4

Simplify Expressions with Zero Exponents

A special case of the Quotient Property is when the exponents of the numerator and denominator are equal, such as an expression like amam. From earlier work with fractions, we know that

22=11717=1−43−43=1

In words, a number divided by itself is 1. So xx=1, for any x (x0), since any number divided by itself is 1.

The Quotient Property of Exponents shows us how to simplify aman when m>n and when n<m by subtracting exponents. What if m=n?

Now we will simplify amam in two ways to lead us to the definition of the zero exponent.

Consider first 88, which we know is 1.

88=1
Write 8 as 23. 2323=1
Subtract exponents. 233=1
Simplify. 20=1
This image demonstrates the proof that any non-zero number raised to the power of zero equals one (a^0 = 1), using both exponent rules and the cancellation of factors.

We see aman simplifies to a a0 and to 1. So a0=1.

In this text, we assume any variable that we raise to the zero power is not zero.

Simplify:
  1. 120
  2. y0
Solution

Solution

The definition says any non-zero number raised to the zero power is 1.

Illustrates the evaluation of 12^0 by applying the definition of the zero exponent, resulting in 1.
120
Use the definition of the zero exponent. 1
This table illustrates the zero exponent rule, showing that y^0 simplifies to 1 based on its definition.
y0
Use the definition of the zero exponent. 1

Now that we have defined the zero exponent, we can expand all the Properties of Exponents to include whole number exponents.

What about raising an expression to the zero power? Let's look at (2x)0. We can use the product to a power rule to rewrite this expression.

Step-by-step simplification of the expression (2x)^0, demonstrating the application of product to a power and zero exponent rules to arrive at the final value of 1.
(2x)0
Use the Product to a Power Rule. 20x0
Use the Zero Exponent Property. 11
Simplify. 1

This tells us that any non-zero expression raised to the zero power is one.

Simplify: (7z)0.

Solution

Solution

This table demonstrates the zero exponent rule, showing (7z)^0 evaluates to 1.
(7z)0
Use the definition of the zero exponent. 1
Simplify:
  1. (−3x2y)0
  2. −3x2y0
Solution

Solution

This table illustrates the simplification of an expression raised to the zero power, demonstrating the zero exponent rule.
The product is raised to the zero power. (−3x2y)0
Use the definition of the zero exponent. 1
Steps demonstrating the simplification of the algebraic expression -3x^2y^0 using the zero exponent rule.
Notice that only the variable y is being raised to the zero power. −3x2y0
Use the definition of the zero exponent. −3x21
Simplify. −3x2

Simplify Expressions Using the Quotient to a Power Property

Now we will look at an example that will lead us to the Quotient to a Power Property.

Demonstration of simplifying a quotient raised to a power, showing (x/y)^3 expands to x^3/y^3.
(xy)3
This means xyxyxy
Multiply the fractions. xxxyyy
Write with exponents. x3y3

Notice that the exponent applies to both the numerator and the denominator.

We see that (xy)3 is x3y3.

We write:(xy)3x3y3

This leads to the Quotient to a Power Property for Exponents.

An example with numbers may help you understand this property:

(23)3=?2333232323=?827827=827
Simplify:
  1. (58)2
  2. (x3)4
  3. (ym)3
Solution

Solution

The mathematical expression (5/8) squared, representing the fraction five-eighths raised to the power of two.
Use the Quotient to a Power Property, (ab)m=ambm. A mathematical fraction showing 5 squared divided by 8 squared, with the exponents '2' in red, highlighting the power to which both the numerator and denominator are raised.
Simplify. A mathematical fraction displays 25 over 64, with the number 25 positioned above a horizontal division line and the number 64 below it, representing the ratio or division of 25 by 64.
The mathematical expression (x/3) raised to the power of 4.
Use the Quotient to a Power Property, (ab)m=ambm. A mathematical fraction featuring 'x' raised to the 4th power divided by '3' raised to the 4th power, with the exponent '4' colored red in both the numerator and denominator.
Simplify. The mathematical expression x to the power of 4 divided by 81.
A mathematical expression showing the fraction y over m, enclosed in parentheses, all raised to the power of 3.
Raise the numerator and denominator to the third power. A mathematical fraction displaying y cubed divided by m cubed, with the exponents in red.

Simplify Expressions by Applying Several Properties

We'll now summarize all the properties of exponents so they are all together to refer to as we simplify expressions using several properties. Notice that they are now defined for whole number exponents.

Simplify: (x2)3x5.

Solution

Solution

Step-by-step simplification of a rational expression using exponent properties.
(x2)3x5
Multiply the exponents in the numerator, using the
Power Property.
x6x5
Subtract the exponents. x

Simplify: m8(m2)4.

Solution

Solution

This table demonstrates the step-by-step simplification of the exponential expression m^8 / (m^2)^4 to 1, applying exponent properties.
m8(m2)4
Multiply the exponents in the numerator, using the
Power Property.
m8m8
Subtract the exponents. m0
Zero power property 1

Simplify: (x7x3)2.

Solution

Solution

Step-by-step simplification of the algebraic expression (x^7/x^3)^2.
(x7x3)2
Remember parentheses come before exponents, and the
bases are the same so we can simplify inside the
parentheses. Subtract the exponents.
(x73)2
Simplify. (x4)2
Multiply the exponents. x8

Simplify: (p2q5)3.

Solution

Solution

Here we cannot simplify inside the parentheses first, since the bases are not the same.

Steps to simplify a power of a quotient using exponent properties.
(p2q5)3
Raise the numerator and denominator to the third power
using the Quotient to a Power Property, (ab)m=ambm
(p2)3(q5)3
Use the Power Property, (am)n=amn. p6q15

Simplify: (2x33y)4.

Solution

Solution

Step-by-step simplification of the algebraic expression (2x^3 / 3y)^4, demonstrating exponent properties.
(2x33y)4
Raise the numerator and denominator to the fourth
power using the Quotient to a Power Property.
(2x3)4(3y)4
Raise each factor to the fourth power, using the Power
to a Power Property.
24(x3)434y4
Use the Power Property and simplify. 16x1281y4

Simplify: (y2)3(y2)4(y5)4.

Solution

Solution

Illustrates the step-by-step simplification of an algebraic expression by applying various properties of exponents.
(y2)3(y2)4(y5)4
Use the Power Property. (y6)(y8)y20
Add the exponents in the numerator, using the Product Property. y14y20
Use the Quotient Property. 1y6

Divide Monomials

We have now seen all the properties of exponents. We'll use them to divide monomials. Later, you'll use them to divide polynomials.

Find the quotient: 56x5÷7x2.

Solution

Solution

Steps for dividing the monomials 56x^5 by 7x^2, illustrating rewriting as a fraction, separating terms, and applying the Quotient Property.
56x5÷7x2
Rewrite as a fraction. 56x57x2
Use fraction multiplication to separate the number
part from the variable part.
567x5x2
Use the Quotient Property. 8x3

When we divide monomials with more than one variable, we write one fraction for each variable.

Find the quotient: 42x2y3−7xy5.

Solution

Solution

Step-by-step simplification of a rational algebraic expression demonstrating the use of fraction multiplication and quotient property.
42x2y3−7xy5
Use fraction multiplication. 42−7x2xy3y5
Simplify and use the Quotient Property. −6x1y2
Multiply. 6xy2

Find the quotient: 24a5b348ab4.

Solution

Solution

Steps to simplify a rational algebraic expression using fraction multiplication and the quotient property.
24a5b348ab4
Use fraction multiplication. 2448a5ab3b4
Simplify and use the Quotient Property. 12a41b
Multiply. a42b

Once you become familiar with the process and have practiced it step by step several times, you may be able to simplify a fraction in one step.

Find the quotient: 14x7y1221x11y6.

Solution

Solution

Simplification of a rational algebraic expression using the Quotient Property.
14x7y1221x11y6
Simplify and use the Quotient Property. 2y63x4

Be very careful to simplify 1421 by dividing out a common factor, and to simplify the variables by subtracting their exponents.

In all examples so far, there was no work to do in the numerator or denominator before simplifying the fraction. In the next example, we'll first find the product of two monomials in the numerator before we simplify the fraction.

Find the quotient: (3x3y2)(10x2y3)6x4y5.

Solution

Solution

Remember, the fraction bar is a grouping symbol. We will simplify the numerator first.

Step-by-step simplification of a rational algebraic expression using exponent rules.
(3x3y2)(10x2y3)6x4y5
Simplify the numerator. 30x5y56x4y5
Simplify, using the Quotient Rule. 5x

Key Concepts

  • Equivalent Fractions Property
    • If a,b,c are whole numbers where b0,c0, then
      ab=a·cb·canda·cb·c=ab
  • Zero Exponent
    • If a is a non-zero number, then a0=1.
    • Any nonzero number raised to the zero power is 1.
  • Quotient Property for Exponents
    • If a is a real number, a0, and m,n are whole numbers, then
      aman=amn,m>nandaman=1anm,n>m
  • Quotient to a Power Property for Exponents
    • If a and b are real numbers, b0, and m is a counting number, then
      (ab)m=ambm
    • To raise a fraction to a power, raise the numerator and denominator to that power.

Practice Makes Perfect

Simplify Expressions Using the Quotient Property of Exponents

In the following exercises, simplify.

4842

Solution

46

31234

x12x3

Solution

x9

u9u3

r5r

Solution

r4

y4y

y4y20

Solution

1y16

x10x30

1031015

Solution

11012

r2r8

aa9

Solution

1a8

225

Simplify Expressions with Zero Exponents

In the following exercises, simplify.

50

Solution

1

100

a0

Solution

1

x0

70

Solution

−1

40

  1. (10p)0
  2. 10p0
Solution
  1. 1
  2. 10
  1. (3a)0
  2. 3a0
  1. (−27x5y)0
  2. −27x5y0
Solution
  1. 1
  2. −27x5
  1. (−92y8z)0
  2. −92y8z0
  1. 150
  2. 151
Solution
  1. 1
  2. 15
  1. 60
  2. 61

2·x0+5·y0

Solution

7

8·m04·n0

Simplify Expressions Using the Quotient to a Power Property

In the following exercises, simplify.

(32)5

Solution

24332

(45)3

(m6)3

Solution

m3216

(p2)5

(xy)10

Solution

x10y10

(ab)8

(a3b)2

Solution

a29b2

(2xy)4

Simplify Expressions by Applying Several Properties

In the following exercises, simplify.

(x2)4x5

Solution

x3

(y4)3y7

(u3)4u10

Solution

u2

(y2)5y6

y8(y5)2

Solution

1y2

p11(p5)3

r5r4·r

Solution

1

a3·a4a7

(x2x8)3

Solution

1x18

(uu10)2

(a4·a6a3)2

Solution

a14

(x3·x8x4)3

(y3)5(y4)3

Solution

y3

(z6)2(z2)4

(x3)6(x4)7

Solution

1x10

(x4)8(x5)7

(2r35s)4

Solution

16r12625s4

(3m24n)3

(3y2·y5y15·y8)0

Solution

1

(15z4·z90.3z2)0

(r2)5(r4)2(r3)7

Solution

1r3

(p4)2(p3)5(p2)9

(3x4)3(2x3)2(6x5)2

Solution

3x8

(−2y3)4(3y4)2(−6y3)2

Divide Monomials

In the following exercises, divide the monomials.

48b8÷6b2

Solution

8b6

42a14÷6a2

36x3÷(−2x9)

Solution

−18x6

20u8÷(−4u6)

18x39x2

Solution

2x

36y94y7

−35x7−42x13

Solution

56x6

18x5−27x9

18r5s3r3s9

Solution

6r2s8

24p7q6p2q5

8mn1064mn4

Solution

n68

10a4b50a2b6

−12x4y915x6y3

Solution

4y65x2

48x11y9z336x6y8z5

64x5y9z748x7y12z6

Solution

4z3x2y3

(10u2v)(4u3v6)5u9v2

(6m2n)(5m4n3)3m10n2

Solution

10n2m4

(6a4b3)(4ab5)(12a8b)(a3b)

(4u5v4)(15u8v)(12u3v)(u6v)

Solution

5u4v3

Mixed Practice

  1. 24a5+2a5
  2. 24a52a5
  3. 24a52a5
  4. 24a5÷2a5
  1. 15n10+3n10
  2. 15n103n10
  3. 15n103n10
  4. 15n10÷3n10
Solution
  1. 18n10
  2. 12n10
  3. 45n20
  4. 5
  1. p4p6
  2. (p4)6
  1. q5q3
  2. (q5)3
Solution
  1. q8
  2. q15
  1. y3y
  2. yy3
  1. z6z5
  2. z5z6
Solution
  1. z
  2. 1z

(8x5)(9x)÷6x3

(4y)(12y7)÷8y2

Solution

6y6

27a73a3+54a99a5

32c114c5+42c96c3

Solution

15c6

32y58y260y105y7

48x66x435x97x7

Solution

3x2

63r6s39r4s272r2s26s

56y4z57y3z345y2z25y

Solution

yz2

Everyday Math

Memory One megabyte is approximately 106 bytes. One gigabyte is approximately 109 bytes. How many megabytes are in one gigabyte?

Memory One megabyte is approximately 106 bytes. One terabyte is approximately 1012 bytes. How many megabytes are in one terabyte?

Solution

1,000,000

Writing Exercises

Vic thinks the quotient x20x4 simplifies to x5. What is wrong with his reasoning?

Mai simplifies the quotient y3y by writing y3y=3. What is wrong with her reasoning?

Solution

Answers will vary.

When Dimple simplified 30 and (−3)0 she got the same answer. Explain how using the Order of Operations correctly gives different answers.

Roxie thinks n0 simplifies to 0. What would you say to convince Roxie she is wrong?

Solution

Answers will vary.

Self Check

After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

A math self-assessment sheet listing various exponent properties and monomial division skills, with columns for students to rate their proficiency: Confidently, With some help, or No-I don't get it!.

On a scale of 1–10, how would you rate your mastery of this section in light of your responses on the checklist? How can you improve this?

zero exponent
If a is a non-zero number, then a0=1. Any nonzero number raised to the zero power is 1.