Given that xy > 0, which of the following must also be greater than zero?
(A) x + y
(B) x^2 + y
(C) (x + y)^2
(D) x^2 - y^2 + 100
(E) (x - y)^2
For a discussion of plugging in numbers, as well as a full solution to this question, see:
http://magoosh.com/gmat/2013/how-to-plu ... questions/
Mike![:-)]( "Smile")
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(A) x + y
(B) x^2 + y
(C) (x + y)^2
(D) x^2 - y^2 + 100
(E) (x - y)^2
For a discussion of plugging in numbers, as well as a full solution to this question, see:
http://magoosh.com/gmat/2013/how-to-plu ... questions/
Mike
