must be true

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must be true

by grandh01 » Tue Sep 18, 2012 9:03 pm
If x and y are different integers and x2
= xy, which of the following must be
true?
â… . x = 0
â…¡. y = 0
â…¢. x = -y
(A) â…  only
(B) â…¡only
(C) â…¢ only
(D) â… and â…¢ only
(E) â… ,â…¡and â…¢

OA IS A

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by Anurag@Gurome » Tue Sep 18, 2012 10:00 pm
grandh01 wrote:If x and y are different integers and x2
= xy, which of the following must be
true?
â… . x = 0
â…¡. y = 0
â…¢. x = -y
(A) â…  only
(B) â…¡only
(C) â…¢ only
(D) â… and â…¢ only
(E) â… ,â…¡and â…¢

OA IS A
x² = xy implies x² - xy = 0 implies x(x - y) = 0, which means either x = 0 or x = y. But it is given that x and y are different integers, so x = y cannot be true. Hence, x = 0 holds true.

The correct answer is A.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

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