If x2/9 – 4/y2 ....

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If x2/9 – 4/y2 ....

by factor26 » Sun Oct 09, 2011 12:59 pm
If x2/9 - 4/y2 = 12, what is the value of x?

(1) x/3 + 2/y = 6

(2) x/3 - 2/y = 2

Answer is D ... can anyone provide step by step instructions on how to solve?

Thanks!

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by gmatclubmember » Sun Oct 09, 2011 1:11 pm
factor26 wrote:If x2/9 - 4/y2 = 12, what is the value of x?

(1) x/3 + 2/y = 6

(2) x/3 - 2/y = 2

Answer is D ... can anyone provide step by step instructions on how to solve?

Thanks!
(x/3-2/y)(x/3+2/y)=12--------(a)
now if we consider 1 only then we can substitute the value of
x/3+2/y =6--------(b)
into our equation (a) above and get x/3-2/y=2-------(c) now b and c can be sloved to get the value of x and y.
so 1 is SUFFICIENT
Similarly
2 is SuFFICIENT.


hence answer is D.
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