Algebra II : Understanding Exponents

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #3292 : Algebra Ii

Simplify: \displaystyle 9^{\frac{1}{9}}

Possible Answers:

\displaystyle 1

\displaystyle \sqrt[9]{9}

\displaystyle 3

\displaystyle -\sqrt[9]{9}

\displaystyle \frac{1}{\sqrt[9]{9}}

Correct answer:

\displaystyle \sqrt[9]{9}

Explanation:

When dealing with fractional exponents, we rewrite as such: \displaystyle x^{\frac{a}{b}}=\sqrt[b]{x^a} which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle x.

\displaystyle 9^{\frac{1}{9}}=\sqrt[9]{9}

Example Question #631 : Mathematical Relationships And Basic Graphs

Simplify: \displaystyle 16^{-\frac{2}{3}}

Possible Answers:

\displaystyle -\sqrt[3]{256}

\displaystyle 64

\displaystyle \frac{1}{\sqrt[3]{256}}

\displaystyle \sqrt[3]{256}

\displaystyle -\frac{1}{\sqrt[3]{256}}

Correct answer:

\displaystyle \frac{1}{\sqrt[3]{256}}

Explanation:

When dealing with fractional exponents, we rewrite as such: \displaystyle x^{\frac{a}{b}}=\sqrt[b]{x^a} which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle x. When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle 16^{-\frac{2}{3}}=\frac{1}{\sqrt[3]{16^2}}=\frac{1}{\sqrt[3]{256}}

Example Question #161 : Exponents

Simplify: \displaystyle 20^{-\frac{2}{5}}

Possible Answers:

\displaystyle \sqrt[5]{400}

\displaystyle -\sqrt[5]{400}

\displaystyle 8

\displaystyle -\frac{1}{8}

\displaystyle \frac{1}{\sqrt[5]{400}}

Correct answer:

\displaystyle \frac{1}{\sqrt[5]{400}}

Explanation:

When dealing with fractional exponents, we rewrite as such: \displaystyle x^{\frac{a}{b}}=\sqrt[b]{x^a} which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle x. When dealing with negative exponents, we convert to fractions as such: \displaystyle x^{-a}=\frac{1}{x^a} which \displaystyle a is the positive exponent raising base \displaystyle x.

\displaystyle 20^{-\frac{2}{5}}=\frac{1}{\sqrt[5]{20^2}}=\frac{1}{\sqrt[5]{400}}

Example Question #161 : Understanding Exponents

Simplify: \displaystyle \frac{1}{4}^{\frac{1}{2}}

Possible Answers:

\displaystyle \frac{1}{8}

\displaystyle 2

\displaystyle \frac{1}{2}

\displaystyle \frac{1}{16}

\displaystyle \frac{1}{12}

Correct answer:

\displaystyle \frac{1}{2}

Explanation:

When dealing with fractional exponents, we rewrite as such: \displaystyle x^{\frac{a}{b}}=\sqrt[b]{x^a} which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle x.

\displaystyle \frac{1}{4}^{\frac{1}{2}}=\sqrt{\frac{1}{4}}=\frac{1}{2}

Example Question #631 : Mathematical Relationships And Basic Graphs

Simplify:

\displaystyle a^{\frac{1}{4}}

where \displaystyle a=3x^4y^8

Possible Answers:

\displaystyle xy\sqrt[4]{3}

\displaystyle x^2y^4\sqrt[4]{3}

\displaystyle xy^2\sqrt[4]{3}

\displaystyle 81x^{16}y^{32}

Correct answer:

\displaystyle xy^2\sqrt[4]{3}

Explanation:

When dealing with fractional exponents, remember that the numerator of the fraction represents the power to which we are taking the term that has the exponent, and the denominator represents the degree of the root we are taking of that term.

For our expression, the numerator is 1, which means we raise a to the first power. The denominator is 4, which means we are taking the fourth root of the term:

\displaystyle \sqrt[4]{(3x^4y^8)^1}

We can only move the cubes out of the radical, and when we do so, we get

\displaystyle xy^2\sqrt[4]{3}

Example Question #161 : Exponents

Evaluate \displaystyle 17^\frac{1}{2}

Possible Answers:

\displaystyle 34

\displaystyle \sqrt{17}

\displaystyle \sqrt{8.5}

\displaystyle 8.5

\displaystyle -17

Correct answer:

\displaystyle \sqrt{17}

Explanation:

When dealing with fractional exponents, we rewrite as such: 

\displaystyle x^\frac{a}{b}=\sqrt[b]{x^a} 

in which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle a.

\displaystyle 17^\frac{1}{2}=\sqrt{17}

Example Question #162 : Understanding Exponents

Evaluate \displaystyle 18^\frac{2}{3}

Possible Answers:

\displaystyle 8\sqrt{2}

\displaystyle \sqrt[3]{324}

\displaystyle \sqrt{5832}

\displaystyle \sqrt[3]{54}

\displaystyle 12

Correct answer:

\displaystyle \sqrt[3]{324}

Explanation:

When dealing with fractional exponents, we rewrite as such: 

\displaystyle x^\frac{a}{b}=\sqrt[b]{x^a} 

in which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle a.

\displaystyle 18^\frac{2}{3}=\sqrt[3]{18^2}=\sqrt[3]{324}

Example Question #41 : Fractional Exponents

Evaluate \displaystyle 24^\frac{2}{5}

Possible Answers:

\displaystyle 9.6

\displaystyle 24\sqrt{2}

\displaystyle 2\sqrt[5]{2}

\displaystyle 2\sqrt[5]{18}

\displaystyle \sqrt[5]{676}

Correct answer:

\displaystyle 2\sqrt[5]{18}

Explanation:

When dealing with fractional exponents, we rewrite as such: 

\displaystyle x^\frac{a}{b}=\sqrt[b]{x^a} 

in which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle a.

\displaystyle 24^\frac{2}{5}=\sqrt[5]{24^2}=\sqrt[5]{576}=2\sqrt[5]{18} 

We were able to simplify it by factoring out perfect fifth root.

In this case, it was \displaystyle 32 =2^5.

 

Example Question #51 : Fractional Exponents

Evaluate \displaystyle \frac{1}{2}^\frac{1}{2}

Possible Answers:

\displaystyle -\sqrt{2}

\displaystyle \frac{\sqrt{2}}{2}

\displaystyle \frac{\sqrt{2}}{4}

\displaystyle \frac{1}{4}

\displaystyle \sqrt{2}

Correct answer:

\displaystyle \frac{\sqrt{2}}{2}

Explanation:

When dealing with fractional exponents, we rewrite as such: 

\displaystyle x^\frac{a}{b}=\sqrt[b]{x^a} 

in which \displaystyle b is the index of the radical and \displaystyle a is the exponent raising base \displaystyle a.

\displaystyle \frac{1}{2}^\frac{1}{2}=\sqrt{\frac{1}{2}}=\frac{1}{\sqrt{2}}=\frac{\sqrt{2}}{2} 

Remember when getting rid of radicals, we just multiply top and bottom by the radical.

Example Question #51 : Fractional Exponents

Simplify:

\displaystyle (9x)^{\frac{2}{3}}+(10x)^{\frac{3}{2}}

Possible Answers:

\displaystyle 3x\sqrt[3]{3x}+10x\sqrt{10x}

\displaystyle 3\sqrt[3]{3x^2}-10x\sqrt{10x}

\displaystyle 3\sqrt[3]{9x^2}+10x\sqrt{10x}

\displaystyle 3\sqrt[3]{3x^2}+10x\sqrt{10x}

Correct answer:

\displaystyle 3\sqrt[3]{3x^2}+10x\sqrt{10x}

Explanation:

To simplify fractional exponents, remember that the numerator of the fraction corresponds to the power the term is taken, and the denominator indicates what root we are taking of that term (i.e. 2 means square root, 3 means cube root and so on).

Doing this, we get

\displaystyle \sqrt[3]{(9x)^2}+\sqrt{(10x)^3}

Expanding the inside of the roots, we get

\displaystyle \sqrt[3]{81x^2}+\sqrt{1000x^3}

We can now factor the terms on the inside, pulling out any cubes or squares, respectively:

\displaystyle \sqrt[3]{27\cdot 3\cdot x^2} +\sqrt{100\cdot 10\cdot x^2\cdot x}=3\sqrt[3]{3x^2}+10x\sqrt{10x}

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