ds 20

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ds 20

by dunkin77 » Thu May 31, 2007 4:26 am
Hi,

The answer is B) but I still dont understand...


What I understood from Q is..

2) X<0

Can anyone explain ?
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by mschling52 » Thu May 31, 2007 5:40 am
I think B is the answer. We know the left side of the equation,

sqrt((x-3)^2) = +/- (x-3) = (x-3) or (3-x),

which are the positive and negative square roots of (x-3)^2. Since the radical sign refers to the positive square root, we are asked if the positive square root is equal to 3-x. So, if we know the sign of 3-x, we can answer the question.

(1) is not sufficient, but (2) gives us that x<0 as you pointed out. Therefore 3-x must be greater than 0, so that 3-x is the positive square root of (x-3)^2.