So with this polynomial, I will be completing the square. Firstly, what two terms have a product of 32x^2 and a sum of -12x? That would be -8x and -4x. Replace -12x with -4x - 8x:

Next, factor x^2 - 4x and -8x + 32 separately. Make sure that they have the same quantity in the parentheses:

Now you can rewrite your expression as
, and your factors are (x - 8) and (x - 4).