It seems there are times where its possible to arrive at different factoring results. For instance view this problem from the book:

Books Solution:

$\displaystyle 30x^4-6x^2 = 6x^2(5x^2-1)$

My Solution:

$\displaystyle 30x^4-6x^2 = 3x^2(10x^2-2)$

Both factoring results seem to be correct.