Inequalities and Factoring Question from GMAT Focus

[hkparikh09]

This question is from GMATFocus.com, so I can't post the entire question; I'll just ask about the part that is stumping me:

Data Sufficiency question
One of the statement reads

X^3 = 3X

We basically need to find possible values for X. My factoring method is different from GMAT's factoring method:

My method: (X^3) - (3X) = 0

X (X^2 -3) = 0

So X can = 0 or pos or neg sqrt of 3

GMAT's Explanation:
(X^3) - (3X) = 0 same as what I did

however, the GMAT factored in a different way:
X^2 (X - 3) = 0

So the GMAT's solutions are X = 0 or 3
I don't see how this is a correct way of factoring. Can someone explain what I did wrong and why GMAT's method works? Is it possible that GMAC made a mistake?

Thank you.

[jlucero]

Yeah, your math looks right here. I don't have the question in front of me, but a Google search seems to show that at least one other person agrees that the question is worded incorrectly. Bizarre.