eybrj2 wrote:
If x and y are positive, what is the value of x-y?
(1) (x^2 - y^2)/ (x + y) = 4
(2) x + y = 7
Target question: What is the value of x-y?
Given: x and y are positive
Statement 1: (x² - y²)/(x + y) = 4
Factor the numerator to get: (x - y)(x + y)(x + y) = 4
Simplify:(x - y) = 4 PERFECT!
Since we can answer thetarget question with certainty, statement 1 is SUFFICIENT
Statement 2: x + y = 7 There are several values of x and y that satisfy statement 2. Here are two:
Case a x = 6
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