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crackgmat007
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What is the value of a^4-b^4
1. a^2-b^2=16
2. a+b=8
Pls clarify why statement 1 alone is not sufficient. Using statement 1, i got (a+b)(a-b) = 16. Since (a+b) * (a-b) must result in 16, using plug ins, I got a=5 and b=3.
However, OA - C Pls clarify if I am missing something
1. a^2-b^2=16
2. a+b=8
Pls clarify why statement 1 alone is not sufficient. Using statement 1, i got (a+b)(a-b) = 16. Since (a+b) * (a-b) must result in 16, using plug ins, I got a=5 and b=3.
However, OA - C Pls clarify if I am missing something
