Răspuns :


E(x)=[3(4x-2)-(x-6)][3(4x-2)+(x-6)]
E(x)=(12x-6-x+6)(12x-6+x-6)=11x(13x-12)
9(4x-2)la a 2-(x+6) la a 2
9(16x^2-16x+4)-(x^2+12x+36)=
144x^2-144x+36-x^2-12x-36=
143x^2-156x=
x(143x-156)