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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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Quotient Rules for Exponents

Suppose you have the expression:

xxxxxxxxxyyyyyxxxxxxyyy\begin{align*}\frac{x\cdot x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot y \cdot y \cdot y \cdot y \cdot y}{x\cdot x \cdot x \cdot x \cdot x \cdot x \cdot y \cdot y \cdot y}\end{align*}

How could you write this expression in a more concise way?

### Watch This

James Sousa: Simplify Exponential Expressions- Quotient Rule

### Guidance

In the expression x3\begin{align*}x^3\end{align*}, the x\begin{align*}x\end{align*} is called the base and the 3\begin{align*}3\end{align*} is called the exponent. Exponents are often referred to as powers. When an exponent is a positive whole number, it tells you how many times to multiply the base by itself. For example:

• x3=xxx\begin{align*}x^3=x\cdot x \cdot x\end{align*}
• 24=2222=16\begin{align*}2^4=2\cdot 2 \cdot 2 \cdot 2=16\end{align*}.

There are many rules that have to do with exponents (often called the Laws of Exponents) that are helpful to know so that you can work with expressions and equations that involve exponents more easily. Here you will learn two rules that have to do with exponents and quotients.

RULE: To divide two powers with the same base, subtract the exponents.

m factorsaman=(a×a××a)(a×a××a) m>n;a0 n factorsaman=(a×a××a) mn factorsaman=amn

RULE: To raise a quotient to a power, raise both the numerator and the denominator to the power.

(ab)n=ab×ab××ab n factorsn factors (ab)n=(a×a××a)(b×b××b) n factors(ab)n=anbn (b0)

#### Example A

Simplify 27÷23\begin{align*}2^7 \div 2^3\end{align*}.

Solution:

27÷2327324The base is 2.Keep the base of 2 and subtract the exponents.The answer is in exponential form.

The answer can be taken one step further. The base is numerical so the term can be evaluated.

24=2×2×2×224=1627÷23=24=16

#### Example B

Simplify x8x2\begin{align*}\frac{x^8}{x^2}\end{align*}.

Solution:

x8x2x82x6x8x2=x6The base is x.Keep the base of x and subtract the exponents.The answer is in exponential form.

#### Example C

Simplify 16x5y54x2y3\begin{align*}\frac{16x^5 y^5}{4x^2 y^3}\end{align*}.

Solution:

16x5y54x2y34(x5y5x2y3)4x52y534x3y2The bases are x and y.Divide the coefficients - 16÷4=4. Keep the base of x and y andsubtract the exponents of the same base.

#### Concept Problem Revisited

xxxxxxxxxyyyyyxxxxxxyyy\begin{align*}\frac{x\cdot x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot x \cdot y \cdot y \cdot y \cdot y \cdot y}{x\cdot x \cdot x \cdot x \cdot x \cdot x \cdot y \cdot y \cdot y}\end{align*} can be rewritten as \begin{align*}\frac{x^9y^5}{x^6y^3}\end{align*} and then simplified to \begin{align*}x^3y^2\end{align*}.

### Guided Practice

Simplify each of the following expressions.

1. \begin{align*}\left(\frac{2}{3}\right)^2\end{align*}

2. \begin{align*}\left(\frac{x}{6}\right)^3\end{align*}

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

1. \begin{align*}\left(\frac{2}{3}\right)^2=\frac{2^2}{3^2}=\frac{4}{9}\end{align*}

2. \begin{align*}\left(\frac{x}{6}\right)^3=\frac{x^3}{6^3}=\frac{x^3}{216}\end{align*}

3. \begin{align*}\left(\frac{3x}{4y}\right)^2=\frac{3^2x^2}{4^2y^2}=\frac{9x^2}{16y^2}\end{align*}

### Explore More

Simplify each of the following expressions, if possible.

1. \begin{align*}\left(\frac{2}{5}\right)^6\end{align*}
2. \begin{align*}\left(\frac{4}{7}\right)^3\end{align*}
3. \begin{align*}\left(\frac{x}{y}\right)^4\end{align*}
4. \begin{align*}\frac{20x^4y^5}{5x^2y^4}\end{align*}
5. \begin{align*}\frac{42x^2y^8z^2}{6xy^4z}\end{align*}
6. \begin{align*}\left(\frac{3x}{4y}\right)^3\end{align*}
7. \begin{align*}\frac{72x^2y^4}{8x^2y^3}\end{align*}
8. \begin{align*}\left(\frac{x}{4}\right)^5\end{align*}
9. \begin{align*}\frac{24x^{14}y^8}{3x^5y^7}\end{align*}
10. \begin{align*}\frac{72x^3y^9}{24xy^6}\end{align*}
11. \begin{align*}\left(\frac{7}{y}\right)^3\end{align*}
12. \begin{align*}\frac{20x^{12}}{-5x^8}\end{align*}
1. Simplify using the laws of exponents: \begin{align*}\frac{2^3}{2^5}\end{align*}
2. Evaluate the numerator and denominator separately and then simplify the fraction: \begin{align*}\frac{2^3}{2^5}\end{align*}
3. Use your result from the previous problem to determine the value of \begin{align*}a\end{align*}: \begin{align*}\frac{2^3}{2^5}=\frac{1}{2^{a}}\end{align*}
4. Use your results from the previous three problems to help you evaluate \begin{align*}2^{-4}\end{align*}.

### Vocabulary Language: English

Base

Base

When a value is raised to a power, the value is referred to as the base, and the power is called the exponent. In the expression $32^4$, 32 is the base, and 4 is the exponent.
Exponent

Exponent

Exponents are used to describe the number of times that a term is multiplied by itself.
Power

Power

The "power" refers to the value of the exponent. For example, $3^4$ is "three to the fourth power".