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If y= square root of 0.36x^8, then y =

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If y= square root of 0.36x^8, then y = [#permalink]  21 Jun 2017, 02:19
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Question Stats:

99% (00:52) correct 0% (00:00) wrong based on 7 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

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Re: If y= square root of 0.36x^8, then y = [#permalink]  01 Feb 2018, 11:19
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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
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Re: If y= square root of 0.36x^8, then y = [#permalink]  01 Feb 2018, 13:30
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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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Re: If y= square root of 0.36x^8, then y =   [#permalink] 01 Feb 2018, 13:30
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