Sqroot problem in GMATPrep2

[gurpreetsingh.1982]

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.

[sam2304]

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

[gurpreetsingh.1982]

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!

[dabral]

Two methods to approach this problem.

Dabral