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# Exponential Properties Involving Quotients

## Subtract exponents to divide exponents by other exponents

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Practice Exponential Properties Involving Quotients
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Chapter 9 -- Concept 9.2: Exponential Properties Involving Quotients (Lesson)

Suppose you wanted to know the volume of a cube and the area of one of its bases. If the length of one of its edges was s\begin{align*}s\end{align*}, what would be the volume of the cube? What would be its base area? Knowing that you could find the height of the cube by dividing its volume by its base area, what expression could you write to represent this quotient? In this Concept, you'll learn about exponential properties involving quotients so that you can perform division problems such as this one.

### Guidance

In this Concept, you will learn how to simplify quotients of numbers and variables.

Quotient of Powers Property: For all real numbers χ,χnχm=χnm\begin{align*}\chi, \frac{\chi^n}{\chi^m} =\chi^{n-m}\end{align*}.

When dividing expressions with the same base, keep the base and subtract the exponent in the denominator (bottom) from the exponent in the numerator (top). When we have problems with different bases, we apply the rule separately for each base.

#### Example A

Simplify \begin{align*}\frac{x^7}{x^4}\end{align*}.

Solution: To simplify \begin{align*}\frac{x^7}{x^4}\end{align*}, repeated multiplication can be used.

\begin{align*}\frac{x^7}{x^4} &= \frac{\cancel{x} \cdot \cancel{x} \cdot \cancel{x} \cdot \cancel{x} \cdot x \cdot x \cdot x}{\cancel{x} \cdot \cancel{x} \cdot \cancel{x} \cdot \cancel{x}}=\frac{x \cdot x \cdot x}{1}=x^3\\ \frac{x^5y^3}{x^3y^2} &= \frac{\cancel{x} \cdot \cancel{x} \cdot \cancel{x} \cdot x \cdot x}{\cancel{x} \cdot \cancel{x} \cdot \cancel{x}} \cdot \frac{\cancel{y} \cdot \cancel{y} \cdot y}{\cancel{y} \cdot \cancel{y}}=\frac{x \cdot x}{1} \cdot \frac{y}{1}=x^2 y \ \text{OR} \ \frac{x^5y^3}{x^3y^2}=x^{5-3} \cdot y^{3-2}=x^2y\end{align*}

#### Example B

Simplify each of the following expressions using the quotient rule.

(a) \begin{align*}\frac{x^{10}}{x^5}\end{align*}

(b) \begin{align*}\frac{x^5 \gamma^4}{x^3 \gamma^2}\end{align*}

Solution:

(a) \begin{align*}\frac{x^{10}}{x^5}=\chi^{10-5}=\chi^5\end{align*}

(b) \begin{align*}\frac{x^5 \gamma^4}{x^3 \gamma^2}=\chi^{5-3} \cdot \gamma^{4-2}=\chi^2 \gamma^2\end{align*}

Power of a Quotient Property: \begin{align*}\left(\frac{\chi^n}{\gamma^m}\right)^p = \frac{\chi^{n \cdot p}}{\gamma^{m \cdot p}}\end{align*}

The power inside the parenthesis for the numerator and the denominator multiplies with the power outside the parenthesis. The situation below shows why this property is true.

#### Example C

Simplify \begin{align*}\left(\frac{x^3}{y^2}\right)^4\end{align*}.

\begin{align*}\left(\frac{x^3}{y^2}\right)^4=\left( \frac{x^3}{y^2} \right) \cdot \left( \frac{x^3}{y^2}\right) \cdot \left( \frac{x^3}{y^2} \right) \cdot \left( \frac{x^3}{y^2} \right)=\frac{(x \cdot x \cdot x) \cdot (x \cdot x \cdot x) \cdot (x \cdot x \cdot x) \cdot (x \cdot x \cdot x)}{(y \cdot y) \cdot (y \cdot y) \cdot (y \cdot y) \cdot (y \cdot y)}=\frac{x^{12}}{y^8}\end{align*}

### Guided Practice

Simplify the following expression.

\begin{align*}\left( \frac{x^{10}}{\gamma^5} \right)^3\end{align*}

Solution:

\begin{align*}\left(\frac{x^{10}}{\gamma^5}\right)^3 = \frac{\chi^{10 \cdot 3}}{\gamma^{5 \cdot 3}} = \frac{\chi^{30}}{\gamma^{15}}\end{align*}

### Practice

Sample explanations for some of the practice exercises below are available by viewing the following video. Note that there is not always a match between the number of the practice exercise in the video and the number of the practice exercise listed in the following exercise set. However, the practice exercise is the same in both. CK-12 Basic Algebra: Exponent Properties Involving Quotients (9:22)

Evaluate the following expressions.

1. \begin{align*}\frac{5^6}{5^2}\end{align*}
2. \begin{align*}\frac{6^7}{6^3}\end{align*}
3. \begin{align*}\frac{3^{10}}{3^4}\end{align*}
4. \begin{align*}\left(\frac{2^2}{3^3}\right)^3\end{align*}

Simplify the following expressions.

1. \begin{align*}\frac{a^3}{a^2}\end{align*}
2. \begin{align*}\frac{x^9}{x^5}\end{align*}
3. \begin{align*}\frac{x^{10}}{x^5}\end{align*}
4. \begin{align*}\frac{a^6}{a}\end{align*}
5. \begin{align*}\frac{a^5b^4}{a^3b^2}\end{align*}
6. \begin{align*}\frac{4^5}{4^2}\end{align*}
7. \begin{align*}\frac{5^3}{5^7}\end{align*}
8. \begin{align*}\left( \frac{3^4}{5^2} \right)^2\end{align*}
9. \begin{align*}\left( \frac{a^3b^4}{a^2b} \right)^3\end{align*}
10. \begin{align*}\frac{x^6y^5}{x^2y^3}\end{align*}
11. \begin{align*}\frac{6x^2y^3}{2xy^2}\end{align*}
12. \begin{align*}\left( \frac{2a^3b^3}{8a^7b} \right)^2\end{align*}
13. \begin{align*}(x^2)^2 \cdot \frac{x^6}{x^4}\end{align*}
14. \begin{align*}\left( \frac{16 a^2}{4b^5} \right)^3 \cdot \frac{b^2}{a^{16}}\end{align*}
15. \begin{align*}\frac{6a^3}{2a^2}\end{align*}
16. \begin{align*}\frac{15x^5}{5x}\end{align*}
17. \begin{align*}\left( \frac{18 a^{10}}{15 a^4} \right)^4\end{align*}
18. \begin{align*}\frac{25yx^6}{20 y^5 x^2}\end{align*}
19. \begin{align*}\left( \frac{x^6 y^2}{x^4y^4} \right)^3\end{align*}
20. \begin{align*}\left( \frac{6a^2}{4b^4} \right)^2 \cdot \frac{5b}{3a}\end{align*}
21. \begin{align*}\frac{(3ab)^2(4a^3b^4)^3}{(6a^2b)^4}\end{align*}
22. \begin{align*}\frac{(2a^2bc^2)(6abc^3)}{4ab^2c}\end{align*}

Mixed Review

1. Evaluate \begin{align*}x|z|-|z|\end{align*} when \begin{align*}x=8\end{align*} and \begin{align*}z=-4\end{align*}.
2. Graph the solution set to the system \begin{align*}\begin{cases} y<-x-2 \\ y \ge -6x+3 \end{cases}\end{align*}.
3. Evaluate \begin{align*}\binom{8}{4}\end{align*}.
4. Make up a situation that can be solved by 4!.
5. Write the following as an algebraic sentence: A number cubed is 8.