Question

256 x^2 - 1 328 x - 188

Answer 1

well, you can make the numbers a bit smaller by writing it as

4(64x^2 - 332x - 47)
check the discriminant b^2 - 4ac = 122256
That's not a perfect square, so you cannot factor it with integer coefficients.
Last resort: the quadratic formula.

Unless your question was something different? ...