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#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. # If y= square root of 0.36x^8, then y =  Question banks Downloads My Bookmarks Reviews Important topics
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Moderator  Joined: 18 Apr 2015
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If y= square root of 0.36x^8, then y = [#permalink]
Expert's post 00:00

Question Stats: 86% (00:42) correct 13% (00:36) wrong based on 15 sessions

If $$y= \sqrt{0.36x^8}$$, then y =

A) $$0.06x^2$$

B) $$0.06x^4$$

C) $$0.06x^5$$

D) $$0.6x^2$$

E) $$0.6x^4$$
[Reveal] Spoiler: OA

_________________ Intern Joined: 08 Dec 2017
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Re: If y= square root of 0.36x^8, then y = [#permalink]
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y=sq. root(0.36*x^8) or, y= sq. root(((6/10)*x^4)^2) or, y= 0.6*x^4
So the answer is E. Manager  Joined: 15 Jan 2018
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Re: If y= square root of 0.36x^8, then y = [#permalink]
1
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If y= √(0.36x^8), one way to simplify it would be to split the roots so y = √(.36)√(x^8). Then we can take the square root of them separately. The square root of .36 is .6, since the square root of 36 is 6 and if I need to generate two decimals in the square, I need one decimal in the square root. To put it another way, .6^2 will be .36, since when you multiply two numbers with one decimal place each, the resulting number should have 2 decimals. Now for the second part: √(x^8) must be x^4. To take the square root of any number with an exponent, simply divide the exponent in half. Thus the 8 becomes a 4.

So at the end of all this we have y = .6x^4, or E.

Another way we could've approached this problem is to look at the answer choices and square all of them. Whichever one winds up being the same as everything under the radical must be the correct answer.
_________________

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Need help with GRE math? Check out our ground-breaking books and app. Re: If y= square root of 0.36x^8, then y =   [#permalink] 01 Feb 2018, 13:30
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