Data Sufficiency (DS) | Re: Is x^2 – y^2 a positive number ?

Yes, but I think that in some question the fact that we were dealing with or without integers had some restrictions on whether you could expand or simplify. I wished i could give you more clues[/quote]

x^2 - y^2 = (x - y)(x + y) is true for all numbers - integers, non-integers, positive, negative.

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