X•(2x-1)²-2(x+1)•(x²-x+1)=
= x(4x^2 - 4x +1) -2(x^3 +1) = 4x^3 -4x^2 +x - 2x^3 -2 = 2x^3 - 4x^2 +x -2
x(4x^2-4x+1)-2(x^3+1)=4x^3-4x^2+x-2x^3-2=2x^3-4x^2+x-2