Answer
It makes sense to factor out the GCF first to simplify the polynomial before using other methods of factoring so that the values for $a$, $b$, and $c$ are as low as possible.
Work Step by Step
Example: $256x^2-4y^2$
The GCF of the two terms is $4$, so we factor that out and have the following:
$256x^2-4y^2$
$4(64x^2-y^2)$
We know this is the difference of two squares, so we can factor as such:
$4(64x^2-y^2)$
$4(8x+y)(8x-y)$
If we didn't factor out the GCF, we would have to use the difference of squares formula immediately, so the resulting terms would be larger.
