PSAT Math : Basic Squaring / Square Roots

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : How To Add Square Roots

Simplify the expression:

Possible Answers:

The expression cannot be siimplified further.

Correct answer:

Explanation:

For each of the expressions, factor out a perfect square:

Example Question #2 : How To Add Square Roots

Simplify:

Possible Answers:

The expression cannot be simplified further.

Correct answer:

Explanation:

Simplify each of the radicals by factoring out a perfect square:

Example Question #3 : How To Add Square Roots

Add the square roots into one term:

 

Possible Answers:

None of the other answers

Correct answer:

Explanation:

In order to solve this problem we need to simplfy each of the radicals. By doing this we will get two terms that have the same number under the radical which will allow us to combine the terms. 

 

Example Question #3 : How To Add Square Roots

Simplify:

Possible Answers:

Correct answer:

Explanation:

Remember that you treat square roots like you do variables in the sense that you just add the like factors. In this problem, the only set of like factors is the pair of  values.  Hence:

Do not try to simplify any further!

Example Question #4 : How To Add Square Roots

Simplify:

Possible Answers:

Correct answer:

Explanation:

Begin by simplifying your more complex roots:

This lets us rewrite our expression:

Do the basic multiplications of coefficients:

Reorder the terms:

Finally, combine like terms:

Example Question #1 : How To Multiply Square Roots

Multiply and simplify. Assuming all integers are positive real numbers. 

Possible Answers:

Correct answer:

Explanation:

Multiply the coefficents outside of the radicals.

Then multiply the radicans. Simplify by checking for a perfect square. 

Final answer is your leading coefficent, , multiplied by the answer acquired by multiplying the terms under the radican,

The final answer is .

Example Question #2 : How To Multiply Square Roots

Mulitply and simplify. Assume all integers are positive real numbers. 

Possible Answers:

Correct answer:

Explanation:

Order of operations, first distributing the  to all terms inside the parentheses. 

The final answer is .

Example Question #1 : How To Multiply Square Roots

The square root(s) of 36 is/are ________.

Possible Answers:

-6

6, -6, and 0

6

6 and -6

None of these answers are correct.

Correct answer:

6 and -6

Explanation:

To square a number is to multiply that number by itself. Because 6 x 6 = 36 AND -6 x -6 = 36, both 6 and -6 are square roots of 36.

Example Question #3 : How To Multiply Square Roots

Simplify:

Possible Answers:

Correct answer:

Explanation:

Multiplication of square roots is easy! You just have to multiply their contents by each other. Just don't forget to put the result "under" a square root! Therefore:

becomes

Now, you need to simplify this:

You can "pull out" two s.  (Note, that it would be even easier to do this problem if you factor immediately instead of finding out that .)

After pulling out the s, you get:

Example Question #1 : Basic Squaring / Square Roots

Solve for \dpi{100} x:

x\sqrt{45}+x\sqrt{72}=\sqrt{18}

Possible Answers:

x=3

x=\sqrt{9}

x=\frac{\sqrt{2}}{\sqrt{5}}+\frac{1}{2}

x=\frac{\sqrt{5}}{\sqrt{2}}+2

x=\frac{\sqrt{2}}{\sqrt{5}+2\sqrt{2}}

Correct answer:

x=\frac{\sqrt{2}}{\sqrt{5}+2\sqrt{2}}

Explanation:

x\sqrt{45}+x\sqrt{72}=\sqrt{18}

Notice how all of the quantities in square roots are divisible by 9

x\sqrt{9\times 5}+x\sqrt{9\times 8}=\sqrt{9\times 2}

x\sqrt{9}\sqrt{5}+x\sqrt{9}\sqrt{4\times 2}=\sqrt{9}\sqrt{2}

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

3x\sqrt{5}+6x\sqrt{2}=3\sqrt{2}

x(3\sqrt{5}+6\sqrt{2})=3\sqrt{2}

x=\frac{3\sqrt{2}}{3\sqrt{5}+6\sqrt{2}}

Simplifying, this becomes

x=\frac{\sqrt{2}}{\sqrt{5}+2\sqrt{2}}

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