OK, this was part of an explanation for a Official Guide problem (but I know I can't post the question, so I won't)....
The explanation was that if x^3 is divisible by 9, then x MUST BE divisible by 3.
Is this because we know that x^3 has 3^2 as a factor, and because x is the only source of factors, x must have at least one three as a factor?
So would this hold true for something like x^9 is divisible by 9, so x MUST BE divisible by 3?
I'm just trying to understand the theory as to why this is true and under what circumstances it's true.
Thanks!
mdh