GRE Math : Basic Squaring / Square Roots

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #1 : How To Simplify Square Roots

Simplify (\frac{16}{81})^{1/4}.

Possible Answers:

\frac{2}{3}

\frac{2}{81}

\frac{8}{81}

\frac{4}{81}

\frac{4}{9}

Correct answer:

\frac{2}{3}

Explanation:

(\frac{16}{81})^{1/4}

\frac{16^{1/4}}{81^{1/4}}

\frac{(2\cdot 2\cdot 2\cdot 2)^{1/4}}{(3\cdot 3\cdot 3\cdot 3)^{1/4}}

\frac{2}{3}

Example Question #2 : How To Simplify Square Roots

Simplfy the following radical .

Possible Answers:

Correct answer:

Explanation:

You can rewrite the equation as .

This simplifies to .

Example Question #1 : How To Simplify Square Roots

Which of the following is equal to  ?

Possible Answers:

Correct answer:

Explanation:

√75 can be broken down to √25 * √3. Which simplifies to 5√3.

Example Question #1 : How To Simplify Square Roots

Simplify \sqrt{a^{3}b^{4}c^{5}}.

Possible Answers:

a^{2}b^{2}c\sqrt{ab}

a^{2}bc^{2}\sqrt{ac}

ab^{2}c^{2}\sqrt{ac}

a^{2}b^{2}c^{2}\sqrt{bc}

a^{2}bc\sqrt{bc}

Correct answer:

ab^{2}c^{2}\sqrt{ac}

Explanation:

Rewrite what is under the radical in terms of perfect squares:

x^{2}=x\cdot x

x^{4}=x^{2}\cdot x^{2}

x^{6}=x^{3}\cdot x^{3}

Therefore, \sqrt{a^{3}b^{4}c^{5}}= \sqrt{a^{2}a^{1}b^{4}c^{4}c^{1}}=ab^{2}c^{2}\sqrt{ac}.

Example Question #11 : How To Simplify Square Roots

What is ?

Possible Answers:

Correct answer:

Explanation:

We know that 25 is a factor of 50. The square root of 25 is 5. That leaves  which can not be simplified further.

Example Question #1 : How To Simplify Square Roots

Which of the following is equivalent to \frac{x + \sqrt{3}}{3x + \sqrt{2}}?

Possible Answers:

\frac{3x^{2} -x \sqrt{2} + 3x\sqrt{3} - \sqrt{6}}{9x^{2} - 2}

\frac{4x + \sqrt{5}}{3x + 2}

\frac{3x^{2} - \sqrt{6}}{9x^{2} + 2}

\frac{3x^{2} + \sqrt{6}}{3x - 2}

\frac{3x^{2} + 3x\sqrt{2} + x\sqrt{3} +\sqrt{6}}{9x^{2} - 2}

Correct answer:

\frac{3x^{2} -x \sqrt{2} + 3x\sqrt{3} - \sqrt{6}}{9x^{2} - 2}

Explanation:

Multiply by the conjugate and the use the formula for the difference of two squares:

\frac{x + \sqrt{3}}{3x + \sqrt{2}}

\frac{x + \sqrt{3}}{3x + \sqrt{2}}\cdot \frac{3x - \sqrt{2}}{3x - \sqrt{2}}

\frac{3x^{2} -x \sqrt{2} + 3x\sqrt{3} - \sqrt{6}}{(3x)^{2} - (\sqrt{2})^{2}} 

\frac{3x^{2} -x \sqrt{2} + 3x\sqrt{3} - \sqrt{6}}{9x^{2} - 2}

Example Question #1 : Properties Of Roots And Exponents

Which of the following is the most simplified form of:

 

Possible Answers:

Correct answer:

Explanation:

First find all of the prime factors of 

So 

Example Question #2 : How To Simplify Square Roots

What is  equal to?

Possible Answers:

Correct answer:

Explanation:

 

1. We know that , which we can separate under the square root:

 

2. 144 can be taken out since it is a perfect square: . This leaves us with:

This cannot be simplified any further.

Example Question #21 : Arithmetic

Which of the following is equivalent to:

?

Possible Answers:

Correct answer:

Explanation:

To begin with, factor out the contents of the radicals.  This will make answering much easier:

They both have a common factor .  This means that you could rewrite your equation like this:

This is the same as:

These have a common .  Therefore, factor that out:

Example Question #1 : How To Find The Common Factor Of Square Roots

Simplify:

Possible Answers:

Correct answer:

Explanation:

These three roots all have a  in common; therefore, you can rewrite them:

Now, this could be rewritten:

Now, note that 

Therefore, you can simplify again:

Now, that looks messy! Still, if you look carefully, you see that all of your factors have ; therefore, factor that out:

This is the same as:

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