High School Math : Exponents

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : Exponents

Which of the following is equivalent to \(\displaystyle 3^{-2}\) ? 

Possible Answers:

\(\displaystyle \frac{1}{6}\)

\(\displaystyle 1\)

\(\displaystyle -9\)

\(\displaystyle -6\)

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

Correct answer:

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

Explanation:

By definition, 

\(\displaystyle b^{-x} = \frac{1}{b^{x}}\).

In our problem, \(\displaystyle b = 3\) and \(\displaystyle x = 2\)

Then, we have \(\displaystyle \frac{1}{3^{2}} = \frac{1}{9}\).

Example Question #3135 : Algebra Ii

Solve for \(\displaystyle x\):

\(\displaystyle (x+5)^{-3} = -1\)

Possible Answers:

\(\displaystyle -6\)

\(\displaystyle -5\)

\(\displaystyle -1\)

\(\displaystyle -4\)

\(\displaystyle -3\)

Correct answer:

\(\displaystyle -6\)

Explanation:

Raise both sides of the equation to the inverse power of \(\displaystyle -3\) to cancel the exponent on the left hand side of the equation.

\(\displaystyle \rightarrow ((x+5)^{-3})^{-\frac{1}{3}} = (-1)^{-\frac{1}{3}}\)

\(\displaystyle \rightarrow x+5 = -1\)

Subtract \(\displaystyle 5\) from both sides:

\(\displaystyle \rightarrow (x+5) - 5 = (-1)-5\)

\(\displaystyle \rightarrow x = -6\)

Example Question #1 : Understanding Exponents

Convert the exponent to radical notation.

\(\displaystyle x^{\frac{3}{7}}\)

Possible Answers:

\(\displaystyle \small \small \sqrt[7]{x^3}\)

\(\displaystyle \small \frac{x^3}{x^7}\)

\(\displaystyle \small \small \sqrt[3]{x^7}\)

\(\displaystyle \small \frac{1}{x^4}\)

Correct answer:

\(\displaystyle \small \small \sqrt[7]{x^3}\)

Explanation:

Remember that exponents in the denominator refer to the root of the term, while exponents in the numerator can be treated normally.

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

\(\displaystyle x^{\frac{3}{7}}=\sqrt[7]{x^3}\)

Example Question #1 : Exponents

Which of the following is equivalent to \(\displaystyle 64^{\frac{1}{2}}\) ?

Possible Answers:

\(\displaystyle 32\)

\(\displaystyle 8\)

\(\displaystyle -32\)

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

\(\displaystyle 16\)

Correct answer:

\(\displaystyle 8\)

Explanation:

By definition, a number raised to the \(\displaystyle \frac{1}{2}\) power is the same as the square root of that number. 

Since the square root of 64 is 8, 8 is our solution. 

Example Question #3 : Exponents

Simplify the expression:

\(\displaystyle \small (16^{\frac{1}{2}})(256^{\frac{3}{4}})\)

Possible Answers:

\(\displaystyle 64\)

\(\displaystyle 1024\)

\(\displaystyle 16\)

\(\displaystyle 256\)

Correct answer:

\(\displaystyle 256\)

Explanation:

Remember that fraction exponents are the same as radicals.

\(\displaystyle \small 16^{\frac{1}{2}}=\sqrt{16}=4\)

\(\displaystyle 256^{\frac{3}{4}}=\sqrt[4]{256^3}=64\)

A shortcut would be to express the terms as exponents and look for opportunities to cancel.

\(\displaystyle 16^{\frac{1}{2}}=(4^2)^{\frac{1}{2}}=4\)

\(\displaystyle \small 256^{\frac{3}{4}}=(4^4)^{\frac{3}{4}}=4^3=64\)

Either method, we then need to multiply to two terms.

\(\displaystyle \small (4)(64)=256\)

 

Example Question #4 : Exponents

Simplify the following expression.

\(\displaystyle \frac{4x^3y^8z^2}{8x^6y^2z^4}\)

Possible Answers:

\(\displaystyle \frac{y^6}{2x^3z^2}\)

\(\displaystyle \frac{4y^6}{8x^3z^2}\)

\(\displaystyle \frac{y^4}{2x^2z^2}\)

\(\displaystyle \frac{4y^4}{8x^2z^2}\)

Correct answer:

\(\displaystyle \frac{y^6}{2x^3z^2}\)

Explanation:

When dividing with exponents, the exponent in the denominator is subtracted from the exponent in the numerator. For example: \(\displaystyle \frac{x^3}{x^6}= x^{3-6}=x^{-3}=\frac{1}{x^3}\).

In our problem, each term can be treated in this manner. Remember that a negative exponent can be moved to the denominator.

\(\displaystyle \frac{4x^3y^8z^2}{8x^6y^2z^4}=\frac{4}{8}x^{-3}y^6z^{-2}=\frac{4y^6}{8x^3z^2}\)

Now, simplifly the numerals.

\(\displaystyle \frac{4y^6}{8x^3z^2}=\frac{y^6}{2x^3z^2}\)

Example Question #5 : Exponents

Simplify the following expression. 

 

\(\displaystyle 2^{3} \cdot 2^{6}\)

Possible Answers:

\(\displaystyle 4^{9}\)

\(\displaystyle 2^{18}\)

\(\displaystyle 4^{18}\)

\(\displaystyle 6^{6}\)

\(\displaystyle 2^{9}\)

Correct answer:

\(\displaystyle 2^{9}\)

Explanation:

We are given: \(\displaystyle 2^{3} \cdot 2^{6}\)

Recall that when we are multiplying exponents with the same base, we keep the base the same and add the exponents. 

Thus, we have \(\displaystyle 2^{3 + 6} = 2^{9}\).

Example Question #1 : Simplifying Exponents

Simplify the following expression. 

 

\(\displaystyle \frac{2^{9}}{2^{11}}\)

Possible Answers:

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

\(\displaystyle 2^{\frac{9}{11}}\)

\(\displaystyle \frac{9}{11}\)

\(\displaystyle 2^{2}\)

\(\displaystyle \frac{18}{22}\)

Correct answer:

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

Explanation:

Recall that when we are dividing exponents with the same base, we keep the base the same and subtract the exponents. 

Thus, we have \(\displaystyle \frac{2^{9}}{2^{11}} = 2^{9 - 11} = 2^{-2}\).

We also recall that for negative exponents,

\(\displaystyle b^{-x} = \frac{1}{b^{x}}\).

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

Example Question #9 : Exponents

Simplify the following exponent expression:

\(\displaystyle (\frac{a^{\frac{-3}{2}}}{3^6b^{\frac{-2}{3}}})^{\frac{-1}{2}}\)

Possible Answers:

\(\displaystyle \frac{a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

\(\displaystyle \frac{3a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

\(\displaystyle \frac{9a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

\(\displaystyle \frac{27a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

\(\displaystyle \frac{18a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

Correct answer:

\(\displaystyle \frac{27a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

Explanation:

Begin by rearranging the terms in the numerator and denominator so that the exponents are positive:

\(\displaystyle (\frac{a^{\frac{-3}{2}}}{3^6b^{\frac{-2}{3}}})^{\frac{-1}{2}}\)

\(\displaystyle (\frac{3^6b^{\frac{-2}{3}}}{a^{\frac{-3}{2}}})^{\frac{1}{2}}\)

\(\displaystyle (\frac{3^6a^{\frac{3}{2}}}{b^{\frac{2}{3}}})^{\frac{1}{2}}\)

Multiply the exponents:

\(\displaystyle (\frac{3^3a^{\frac{3}{4}}}{b^{\frac{1}{3}}})\)

Simplify:

\(\displaystyle \frac{27a^{\frac{3}{4}}}{b^{\frac{1}{3}}}\)

Example Question #1 : Exponents

Simplify the expression:

\(\displaystyle x^3 + \frac{2x^2}{x^{-1}}\)

Possible Answers:

\(\displaystyle x^3+2x^2\)

\(\displaystyle x^3+2x\)

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

\(\displaystyle 3x^3\)

\(\displaystyle x^3+2\)

Correct answer:

\(\displaystyle 3x^3\)

Explanation:

First simplify the second term, and then combine the two:

\(\displaystyle x^3 + \frac{2x^2}{x^{-1}}\)

\(\displaystyle = x^3 + 2x^{2-(-1)} = x^3 + 2x^3 = 3x^3\)

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