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by gmatboost » Wed Aug 17, 2011 12:31 pm
Each statement has no constraint on x.

Together:
x^2 + 2x + 2 = 17
x^2 + 2x - 15 = 0
[spoiler](x - 3)(x + 5)
[/spoiler]
[spoiler]x = 3 or x = -5
[/spoiler]
[spoiler]Double check that each one works. x = 3 -> y = 8, x = -5 -> y = -8.[/spoiler]
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by Anurag@Gurome » Thu Aug 18, 2011 5:40 am
GmatKiss wrote:What is x?

(1)x^2 + y = 17
(2)y = 2x + 2
None of the statements individually is sufficient to determine the value of x. So let us consider both of them together. From statement 2, y = (2x + 2)

Hence from statement 1, x^2 + 2x + 2 = 17 ---> x^2 + 2x - 15 = 0
The above quadratic equation will yield two values of x and we cannot determine any unique value of x.

The correct answer is E.
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