Yes! the factors of X^2-4x-12 is (x-6)(x+2) and the 12-4x-x^2 can be transfer what I mean is Arrange them so transfer ×^2 to the left so the sign will change also (from negative to positive) and transfer 12 to the right so the sign will change also (From positive to negative) the -4x will stay its position so it will become x^2-4x-12 (factors (x-6)(x+2) . but if you will not transfer it the factor of 12-4x-x^2 is -(x-6)(x+2). I don't know if you exactly get what I mean