Verified answer

Take (12-2x) common factor

U will get (12-2x)[(12-2x)+2x(-2)] = (12-2x)(12-2x-4x) = (12-2x)(12-6x)

=(12-2x)(12-2x) + (24x-4x^2)(-2)

=144-24x-24x-4x^2+(-48x+8x^2)

=144-24x-24x-4x^2-48x+8x^2

=4x^2+8x^2-48x-24x-24x+144

=12x^2-96x+144

and then you only have to factor it to get (12-2x)(12-6x)