PSAT Math : Factoring and Simplifying Square Roots

Study concepts, example questions & explanations for PSAT Math

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Example Questions

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Example Question #1 :Factoring And Simplifying Square Roots

Solve for\dpi{100} x:

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

Possible Answers:

x=3

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

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

x=\sqrt{9}

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

Example Question #1 :Factoring And Simplifying Square Roots

If m and n are postive integers and 4m= 2n, what is the value of m/n?

Possible Answers:

1/2

2

8

4

16

Correct answer:

1/2

Explanation:
  1. 22= 4. Also, following the rules of exponents, 41= 1.
  2. One can therefore say that m = 1 and n = 2.
  3. The question asks to solve for m/n. Since m = 1 and n = 2, m/n = 1/2.

Example Question #2 :Factoring And Simplifying Square Roots

Simplify the radical:

Possible Answers:

Correct answer:

Explanation:

Example Question #1761 :Psat Mathematics

Simplify. Assume all variables are positive real numbers.

Possible Answers:

Correct answer:

Explanation:

The index coefficent inis represented by. When no index is present, assume it is equal to 2.under the radical is known as the radican, the number you are taking a root of.

First look for a perfect square,

Then to your Variables

Take your exponents on both variables and determine the number of times our index will evenly go into both.

So you would take out aand would be left with a

*Dividing the radican exponent by the index - gives you the number of variables that should be pulled out.

The final answer would be.

Example Question #1 :Factoring And Simplifying Square Roots

Simplify. Assume all integers are positive real numbers.

Possible Answers:

Correct answer:

Explanation:

Index ofmeans the cube root of Radican

Find a perfect cube in

Simplify the perfect cube, giving you.

Take your exponents on both variables and determine the number of times our index will evenly go into both.


The final answer would be

Example Question #1 :How To Simplify Square Roots

Simplify square roots. Assume all integers are positive real numbers.

Simplify as much as possible. List all possible answers.

1a.

1b.

1c.

Possible Answers:

and

andand

andand

andand

Correct answer:

andand

Explanation:

When simplifying radicans (integers under the radical symbol), we first want to look for a perfect square. For example,is not a perfect square. You look to find factors ofto see if there is a perfect square factor in, which there is.

1a.

Do the same thing for.

1b.

1c.Follow the same procedure except now you are looking for perfect cubes.

Example Question #1 :How To Simplify Square Roots

Simplify

9÷√3

Possible Answers:

3√3

2

3

not possible

none of these

Correct answer:

3√3

Explanation:

in order to simplify a square root on the bottom, multiply top and bottom by the root

Asatsimplifysquare_root

Example Question #2 :How To Simplify Square Roots

Simplify:

√112

Possible Answers:

20

4√7

10√12

12

4√10

Correct answer:

4√7

Explanation:

√112 = {√2 * √56} = {√2 * √2 * √28} = {2√28} = {2√4 * √7} = 4√7

Example Question #2 :How To Simplify Square Roots

Simplify:

√192

Possible Answers:
None of these
8√2
4√3
8√3
4√2
Correct answer:8√3
Explanation:

√192 =√2 X√96

√96 =√2 X√48

√48=√4 X√12

√12 =√4 X√3

√192 =√(2X2X4X4) X√3

=√4X√4X√4 X√3

= 8√3

Example Question #1 :How To Simplify Square Roots

What is the simplest way to express\sqrt{3888}?

Possible Answers:

144\sqrt{27}

2\sqrt{972}

2304\sqrt{2}

12\sqrt{27}

Correct answer:

Explanation:

First we will list the factors of 3888:

3888=3\times1296=3\times\3\times432=3^2\times12\times36=3^2\times12\times12\times3=3^2\times12^2\times3

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