help - gmat prep -

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help - gmat prep -

by robzoc » Fri Oct 17, 2008 8:22 am
need help for solving...

thanks
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by vishubn » Fri Oct 17, 2008 8:48 am
Hi !
I am sure this problen has been solved many times! But i could find it myself either

neways !
2^((x+y)^2)/2^((x-y)^2)

2^a/2^b=2^(a-b)

powers simplication :

x^2+y^2+2xy-(x^2+y^2-2xy)

cancel outs and 4xy is left and xy=1

now it is 2^4=16

Vishu

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by vivek.kapoor83 » Fri Oct 17, 2008 8:53 am
2^(x+y)sq - (x-y)sq
2^ (x+y+x-y) (x+y-x+y)
2^(2x)(2y)
2^4xy
xy=1
2^4 =16..ans