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tough gmat prep problem

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tough gmat prep problem

by varun007 » Sun Sep 14, 2008 6:23 am
pls can somebody explain in detail
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by Sunny22uk » Sun Sep 14, 2008 12:36 pm
Since x<0, lets say x=-5
Sqrt of (-x|x|) is Sqrt of 5*5 i.e. +or -5
The answer is -x i.e. -5
Last edited by Sunny22uk on Mon Sep 15, 2008 1:28 pm, edited 1 time in total.
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by pre-gmat » Mon Sep 15, 2008 12:01 pm
I dun think picking values is required here.

Its simpler than that.

sqrt [ -x|x| ]

given x is negative |x| = -x

-x*-x= x ^2

sqrt x^2 = -X or + x

since its given X is negative the answer will be -X
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by Sunny22uk » Mon Sep 15, 2008 12:11 pm
pre-gmat wrote:I dun think picking values is required here.

Its simpler than that.

sqrt [ -x|x| ]

given x is negative |x| = -x

-x*-x= x ^2

sqrt x^2 = -X or + x

since its given X is negative the answer will be -X
Picking values is not Required in any question, It is an alternative strategy :wink:
Also,you cannot write |x| = -x
Absolute value of any non zero number is always positive.
You cannot discover new oceans unless you have the courage to loose sight of the shore.
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