If X < 0 , then SQRT ( ( -x) * |x| ) is equal to?

[kourakis]

If X < 0 , then SQRT ( ( -x) * |x| ) is equal to?

-x , -1, 1, x, SQRTX

Apologies if this has already been posted.

OA is -x. I would say it is X (shouldn't it be |x|?), because a square root is always positive (x^2=4 -- x=+/- 2, but SQRT4 = 2)

Please advise. Thanks!

[mithunsam]

It should be -x.

sqrt(-x *|x|) = sqrt(x * x) --> (Since x < 0, -x = +x. Also, |x| = x)
=sqrt(x^2) =+ x

Now we have to choose between +x and -x. Since x<0, +x will be -ve and -x will be +ve. For sqrt of a number, we have to choose +ve root. Therefore, -x is the correct answer.

[RonPurewal]

please search the forums, people

if-x-0-then-sqrt-x-x-is-t903.html

if you have any further questions about this problem, please post them on that thread; this thread will now be locked. (please read the whole thread before you post a question!)