Sud be A.
A gives=> (x+y)(x-y)=5. We know 5 is a prime so the factors of 5 can only be 5 and 1 or -5 and -1.
But, if we take 5 and 1, then x+y = 5 and x-y = 1. (because x+y > x-y for positive x and y).
The only posisble integer solution for x and y cud be 3 and 2. But 3 and 2 are positive so this solution is ruled out.
so the factor of 5 are actually -5 and -1.
so x-y = -1 and x+y = -5.
Only integer possibility is x=-3 and y = -2
Difference in squares: MGMAT
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Source: Beat The GMAT — Data Sufficiency |
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this_time_i_will
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