carcass wrote:

What is the value of \(x^2 - y^2\) ?

(1) \((x - y)^2 = 9\)

(2) x + y = 6

\(x^2-y^2=(x+y)(x-y)\)

STATEMENTS..

(1) \((x - y)^2 = 9\)

x-y= 3..

x-y=-3..

various combinations of x and y possible fitting in any of two aboveinsuff

(2) x + y = 6

we do not know what is x-yinsuff

combined..

we know x+y=6..

but x-y can be 3, then ans is 18

OR x-y can be -3 ans will be -18insuff

E

_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

GMAT online Tutor