If x2 is even, which of the following must be true? I. x is ... ...
If x is an integer and x2 is even, which of the following must be true?
I. x is odd.
II. x is even.
III. x3 is odd.
(A) I only
(B) ...
(C) ...
(D) ...
(E) ...
*This question is included in
Nova Math - Problem Set A: Substitution
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Posted: 07/04/2012 06:22
I don't get it...
Admin
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RE: I don't get it......
Posted: 10/23/2012 15:33
Grace, this question was not well written, no wonder you are confused. None of the choices apply, and we are in the process of correcting it. Let's take a few examples:
x^2 = 4, x = -2 or 2, so x is even;
x^2 = 8, x = -3 or 3, so x is even;
But let's take x^2 = 6, then x = -√6 or √6, so x is neither even nor odd. And x^3 = 6√6, which is neither odd nor even.
Hence none of the choices are true the way the question was written. We apologize for this error. We will fix it in the next version.
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Posted: 10/06/2014 06:37
Reply: thank u! U've explain the point quite clearly!
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Posted: 07/06/2012 17:21
Suppose x^2 = 6, then x=3 or -3, would answer A not be correct in this case?
Admin
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Posted: 07/18/2012 22:42
Kristy, if x^2=6, then x would be √6 or -√6, not -3 or 3. So, A will not be correct, since x is not odd. In fact it is not an integer.
