ACT Math : How to find the common factor of square roots

Study concepts, example questions & explanations for ACT Math

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Example Questions

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

Possible Answers:

Correct answer:

Explanation:

To solve the equation , we can first factor the numbers under the square roots.

When a factor appears twice, we can take it out of the square root.

Now the numbers can be added directly because the expressions under the square roots match.

Example Question #2 : How To Find The Common Factor Of Square Roots

Solve for .

Possible Answers:

Correct answer:

Explanation:

First, we can simplify the radicals by factoring.

Now, we can factor out the .

Now divide and simplify.

Example Question #3 : How To Find The Common Factor Of Square Roots

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 #3 : Basic Squaring / 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:

Example Question #1 : Factoring Common Factors Of Squares And Square Roots

Simplify:

Possible Answers:

Correct answer:

Explanation:

Begin by factoring out the relevant squared data:

 is the same as

This can be simplified to:

Since your various factors contain square roots of , you can simplify:

Technically, you can factor out a :

Example Question #2 : How To Find The Common Factor Of Square Roots

Solve for :

Possible Answers:

Correct answer:

Explanation:

Begin by breaking apart the square roots on the left side of the equation:

This can be rewritten:

You can combine like terms on the left side:

Solve by dividing both sides by :

This simplifies to:

Example Question #6 : Basic Squaring / Square Roots

Solve for 

Possible Answers:

Correct answer:

Explanation:

To begin solving this problem, find the greatest common perfect square for all quantities under a radical.

 ---> 

Pull  out of each term on the left:

 ---> 

Next, factor out  from the left-hand side:

 ---> 

Lastly, isolate :

 ---> 

Example Question #7 : Basic Squaring / Square Roots

Solve for 

Possible Answers:

Correct answer:

Explanation:

Solving this one is tricky. At first glance, we have no common perfect square to work with. But since each term can produce the quantity , let's start there:

 ---> 

Simplify the first term:

 ---> 

Divide all terms by  to simplify, 

 ---> 

Next, factor out  from the left-hand side:

 ---> 

Isolate  by dividing by  and simplifying:

 ---> 

Last, simplify the denominator:

 ----> 

Example Question #34 : Arithmetic

Solve for :

Possible Answers:

Correct answer:

Explanation:

Right away, we notice that  is a prime radical, so no simplification is possible. Note, however, that both other radicals are divisible by .

Our first step then becomes simplifying the equation by dividing everything by :

 ---> 

Next, factor out  from the left-hand side:

 ---> 

Lastly, isolate :

 ---> 

Example Question #8 : How To Find The Common Factor Of Square Roots

Solve for 

Possible Answers:

Correct answer:

Explanation:

Once again, there are no common perfect squares under the radical, but with some simplification, the equation can still be solved for :

 ---> 

Simplify:

 ---> 

 

Factor out  from the left-hand side:

 ---> 

Lastly, isolate :

 ---> 

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