Algebra II : Distributing Exponents (Power Rule)

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #291 : Simplifying Exponents

Simplify:  \(\displaystyle (3x^4)^{3}\)

Possible Answers:

\(\displaystyle 27x^{7}\)

\(\displaystyle 3x^{12}\)

\(\displaystyle 27x^{12}\)

\(\displaystyle 9x^{12}\)

\(\displaystyle 9x^{7}\)

Correct answer:

\(\displaystyle 27x^{12}\)

Explanation:

To simplify this expression, we will need to multiply the exponents of the inside quantity by the outer exponent.

\(\displaystyle (3x^4)^{3} = (3^{1}\cdot x^4)^{3} = (3^{1\cdot 3 }\cdot x^{4\cdot 3})\)

Simplify the terms by multiplication.

\(\displaystyle 3^3 \cdot x^{12} = 27x^{12}\)

The answer is:  \(\displaystyle 27x^{12}\)

Example Question #291 : Simplifying Exponents

Solve:  \(\displaystyle (2a^8)^{3}\)

Possible Answers:

\(\displaystyle 6a^{11}\)

\(\displaystyle 6a^{24}\)

\(\displaystyle 2a^{11}\)

\(\displaystyle 8a^{11}\)

\(\displaystyle 8a^{24}\)

Correct answer:

\(\displaystyle 8a^{24}\)

Explanation:

In order to solve this expression, use the power rule of exponents.

\(\displaystyle (x^a)^b = x^{ab}\)

Notice that there is also a two in front of the variable.  We will need to convert that as an exponent as well.

\(\displaystyle (2a^8)^{3}=(2^1\cdot a^8)^{3}= 2^3\cdot a^{8\times 3}\)

Simplify the expression.

The answer is:  \(\displaystyle 8a^{24}\)

Example Question #631 : Exponents

Evaluate:   \(\displaystyle 2(4^{10})(8^{20})^3\)

Possible Answers:

\(\displaystyle 2^{1801}\)

\(\displaystyle 2^{71}\)

\(\displaystyle 2^{261}\)

\(\displaystyle 2^{201}\)

\(\displaystyle 2^{70}\)

Correct answer:

\(\displaystyle 2^{201}\)

Explanation:

To evaluate this expression, we will need to convert to common bases in order to use the power rule for exponents.

\(\displaystyle 4=2^2\)

\(\displaystyle 8=2^3\)

Rewrite the problem.

\(\displaystyle 2(4^{10})(8^{20})^3 =2(2^{2(10)})(2^{3(20)})^3= 2\cdot 2^{20}\cdot(2^{60})^3\)

Do not mix the additive rule of exponents with the multiplicative rule.

\(\displaystyle a^b\cdot a^c = a^{b+c}\)

\(\displaystyle (x^y)^z = x^{yz}\)

Use these rules to simplify the terms.

\(\displaystyle 2\cdot 2^{20}\cdot(2^{60})^3 = 2^1\cdot 2^{20}\cdot2^{180} = 2^{1+20+180} =2^{201}\)

The answer is:  \(\displaystyle 2^{201}\)

Example Question #631 : Exponents

Solve:  \(\displaystyle (8^{4})^{15}\)

Possible Answers:

\(\displaystyle 2^{170}\)

\(\displaystyle 2^{60}\)

\(\displaystyle 8^{60}\)

\(\displaystyle 8^{19}\)

\(\displaystyle 4^{80}\)

Correct answer:

\(\displaystyle 8^{60}\)

Explanation:

Use the power rule of exponents to simplify this expression.

\(\displaystyle (x^{Y})^Z = x^{YZ}\)

Follow this rule to simplify the exponents.

\(\displaystyle (8^{4})^{15} = 8^{4\times 15} = 8^{60}\)

The answer is:  \(\displaystyle 8^{60}\)

Example Question #301 : Simplifying Exponents

Simplify:  \(\displaystyle [(2^{-3})^{-2}]^{-\frac{1}{2}}\)

Possible Answers:

\(\displaystyle \frac{1}{64}\)

\(\displaystyle 8\)

\(\displaystyle 4\)

\(\displaystyle \frac{1}{8}\)

\(\displaystyle \frac{1}{32}\)

Correct answer:

\(\displaystyle \frac{1}{8}\)

Explanation:

We can use the power rule of exponents to simplify this expression.

\(\displaystyle (x^{Y})^Z =x^{YZ}\)

\(\displaystyle [(2^{-3})^{-2}]^{-\frac{1}{2}} = 2^{(-3)\cdot (-2 )\cdot( -\frac{1}{2})}\)

The expression becomes:

\(\displaystyle 2^{-3}\)

We can rewrite this as a fraction.

\(\displaystyle 2^{-3} = \frac{1}{2^3}=\frac{1}{8}\)

The answer is:  \(\displaystyle \frac{1}{8}\)

Example Question #116 : Distributing Exponents (Power Rule)

Simplify:  \(\displaystyle b(b^{-3})^{-10}\)

Possible Answers:

\(\displaystyle \frac{1}{b^{14}}\)

\(\displaystyle b^{14}\)

\(\displaystyle b^{31}\)

\(\displaystyle b^{29}\)

\(\displaystyle \frac{1}{b^{12}}\)

Correct answer:

\(\displaystyle b^{31}\)

Explanation:

Use the product rule of exponents to simplify the terms in parentheses.

\(\displaystyle (b^{X})^Y= b^{XY}\)

\(\displaystyle b(b^{-3})^{-10} = b(b^{-3\times -10}) = b(b^{30})\)

This expression is the same as:  \(\displaystyle b^1 \cdot b^{30}\)

The answer is:  \(\displaystyle b^{31}\)

Example Question #301 : Simplifying Exponents

Solve:  \(\displaystyle (5x^3)^4\)

Possible Answers:

\(\displaystyle 5x^{7}\)

\(\displaystyle 5x^{12}\)

\(\displaystyle 20x^{12}\)

\(\displaystyle 625x^{7}\)

\(\displaystyle 625x^{12}\)

Correct answer:

\(\displaystyle 625x^{12}\)

Explanation:

In order to solve this expression, we will need to use the power rule of exponents.

\(\displaystyle (a^{x})^y = a^{xy}\)

We can distribute the outer exponent to the exponents inside the parentheses.  Do not ignore the five, which equals \(\displaystyle 5^1\).

\(\displaystyle (5x^3)^4 = (5^{1\times 4}\cdot x^{3\times 4}) = 5^4 \cdot x^{12}\)

The answer is:  \(\displaystyle 625x^{12}\)

Example Question #303 : Simplifying Exponents

Solve:  \(\displaystyle \frac{1}{2}(64^{5})^{10}\)

Possible Answers:

\(\displaystyle 4^{25}\)

\(\displaystyle 4^{99}\)

\(\displaystyle 2^{299}\)

\(\displaystyle 2^{49}\)

\(\displaystyle 4^{13}\)

Correct answer:

\(\displaystyle 2^{299}\)

Explanation:

In order to solve this, we can change this expression to base two.

The fraction can be rewritten as a negative exponent.

\(\displaystyle \frac{1}{2} =2^{-1}\)

The inner term in the parentheses is equal to:  

\(\displaystyle 64= 2^6\)

Rewrite the expression.

\(\displaystyle \frac{1}{2}(64^{5})^{10} = 2^{-1} (2^{6(5)})^{(10)}\)

Using the product rule of exponents, we can multiply all the powers together.

\(\displaystyle 2^{-1} (2^{6\times 5\times 10})= 2^{-1} (2^{300}) = 2^{-1} \cdot (2^{300})\)

Now that we are multiplying two common bases with exponents, we can add the powers.

\(\displaystyle 2^{-1+300} = 2^{299}\)

The answer is:  \(\displaystyle 2^{299}\)

Example Question #119 : Distributing Exponents (Power Rule)

Solve:  \(\displaystyle 5[(5^3)^4]^5\)

Possible Answers:

\(\displaystyle 5^{18}\)

\(\displaystyle 5^{61}\)

\(\displaystyle 5^{13}\)

\(\displaystyle 5^{12}\)

\(\displaystyle 5^{60}\)

Correct answer:

\(\displaystyle 5^{61}\)

Explanation:

The exponents that are surrounded by the brackets and parentheses can be multiplied based on the product rule for exponents.

\(\displaystyle 5[(5^3)^4]^5 = 5^1\cdot [5^{3\times 4\times 5}] = 5^1\cdot 5^{60}\)

Now that we have bases similar, we can use the additive rule of exponents to combine both terms.

The answer is:  \(\displaystyle 5^{61}\)

Example Question #301 : Simplifying Exponents

Solve:  \(\displaystyle [(3^{-3})^2]^{\frac{1}{2}}\)

Possible Answers:

\(\displaystyle \frac{1}{27}\)

\(\displaystyle 45\)

\(\displaystyle 9\)

\(\displaystyle \frac{1}{9}\)

\(\displaystyle 27\)

Correct answer:

\(\displaystyle \frac{1}{27}\)

Explanation:

According to the product rule of exponents, we can multiply the two powers together in the parentheses.

\(\displaystyle (x^B)^C = x^{B\times C}\)

This means that:

\(\displaystyle (3^{-3})^2 = 3^{-6}\)

Replace this term in the bracket.

\(\displaystyle [(3^{-3})^2]^{\frac{1}{2}} = [3^{-6}]^{\frac{1}{2}}\)

Repeat the process for these exponents.

\(\displaystyle [3^{-6}]^{\frac{1}{2}} = 3^{-6\times \frac{1}{2}} = 3^{-3}\)

This negative exponent can be simplified as a fraction.

\(\displaystyle 3^{-3} = \frac{1}{3^3} = \frac{1}{27}\)

The answer is:  \(\displaystyle \frac{1}{27}\)

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