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pl help

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Senior Manager
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17 Jan 2010, 10:11
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Difficulty:

(N/A)

Question Stats:

33% (02:09) correct 67% (01:25) wrong based on 7 sessions

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Q21:
If x < 0, then √(-x│x│) is
7
A. -x
B. -1
C. 1
D. x
E. √x

OA is
[Reveal] Spoiler:
a
Manager
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17 Jan 2010, 10:35
Since we know that x<0, -(-ve number) = +number, so we can rewrite the eq as:
$$\sqrt{x|x|}$$
=$$\sqrt{x*x}$$
=$$\sqrt{x^2}$$

The answer is always going to be a +ve number. Since we know that x<0, the answer is A.
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17 Jan 2010, 12:27
Check this out: square-root-positive-or-negative-27462.html
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Re: pl help   [#permalink] 17 Jan 2010, 12:27
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