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Sqroot problem in GMATPrep2

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Sqroot problem in GMATPrep2

by gurpreetsingh.1982 » Sat May 12, 2012 1:13 am
Good day,

Spotted this qn in the GMATPrep2 Quiz. Any idea why the answer is not (C)?

If X is negative, -X should be positive X, and the absolute X would be positive X. Hence when multiplied together we should get X^2, and square root of this is X.

Does anyone know why the answer sheet says it's -X (option A)? Thanks.
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by sam2304 » Sat May 12, 2012 1:27 am
You should write the answer in terms of X. You are considering X as a negative value and positive answer would be -x not just x.

Given x < 0. So let x = -5
[-(-5)|-5|]^1/2 = (5*5)^1/2 = 5 = -x
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by gurpreetsingh.1982 » Sat May 12, 2012 2:47 am
Hi Sam,

So because we take X as negative, if we get a negative answer that would be -X. Wow, didn't see that angle coming. Thanks for your advise!
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by dabral » Sat May 12, 2012 3:26 am
Two methods to approach this problem.

Dabral

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