wait can you check if this is right: 8(x^2 + 2x - 8)
if that’s correct, this is the explanation:
first look at all of your terms: 8x^2, 16x, and 64.
find the greatest common factor which is 8 (because all of them have a factor of 8)
factor the 8 out of all of the terms and put an 8 outside of the parenthesis.
you will end up with 8(x^2 + 2x - 8)