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kamalakarthi
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Target question: What is the value of x² - y²?What is the value of x² - y²?
1) x + y = 2x
2) x - y = 0
IMPORTANT: Notice that x² - y² is a DIFFERENCE OF SQUARES, which we can factor to get: (x + y)(x - y).
Statement 1: x + y = 2x
Notice what happens if we rearrange the terms here.
Subtract x from both sides to get: y = x
Subtract y from both sides to get: 0 = x - y
This means that x² - y² = (x + y)(x - y) = (x + y)(0) = 0
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: x - y = 0
This means that x² - y² = (x + y)(x - y) = (x + y)(0) = 0
Since we can answer the target question with certainty, statement 2 is SUFFICIENT
Answer = D
Cheers,
Brent
