Wednesday, September 15, 2010

Is sq rt((x-3)^2) = 3 - x?

(1) x ≠ 3
(2) -x |x| > 0

Rephrase Is |x-3| = 3 -x
if x-3 '>'=0 ; x '>'=3
x-3 = 3-x So x=3;
if x-3 '<' 0; i.e. x '<' 3
-x +3 = 3-x for all values of x

So Q is is x =3 or is x '<' 3

St1 Insuff

St2 tells us that x is negative. Sufficient.

Ans B


i.e. is 3-x '>'= 0 ='>' 3 '>'= x

No comments: