is your problem?
Well, just factoring isn't going to help you (well it will in this case, because its a pretty obvious question).
You want to first arrange your terms, and then solve the resultant equation:
[X^(3/2)]-[X^(1/2)]=0
Factoring out an X^(1/2) and not just a (1/2) yields:
[X^(1/2)][X^(2/2)-1], which is of course just (X-1). From there it should be fairly easy to figure out what you're answers are.