gmat prep Q6

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by smar83 » Tue Jan 29, 2008 7:43 am
Hello,

According to your question:

In the numerator 2^ (x+y)^2 can be written as 2^(x^+2xy+y^2) and for the denominator 2^ (x-y)^2, it can be written as 2^(x^-2xy+y^2) Note: I have used the formula (a+b)^2 = a^2 +2ab+b^2.

Now we know xy=1, so We get as a fraction 2^(x^2+2+y^2)/2^(x^2-2+y^2)... Use the rule of exponents, where we know x^y/x^z = x^(y-z)... if you plug in you get 2^4 =16. And thats your answer.

I hope, I have answered your question.

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by nadontheway » Tue Jan 29, 2008 9:07 am
thanks again!!!!!!!