There are no rational factors.
x^2 - y^2 - 4 is in its simplest form.
(2x - 1)(2x + 3)
-22 - -22
x(x-1)
(x + 2)(x - 4)
(x + 2)(x - 9)
(x - 5)(x + 3)
(x + 1)(x - 8)
x(x - 7)
x(x - 2)
It is not clear what you mean by x^2 minus "factor x". Please add more information and resubmit.