Răspuns :
[tex]x^2-2x+2(x^2-2x+1)+x^2-1-4x^2+4= \\ =x^2-2x+2x^2-4x+2+x^2-1-4x^2+4= \\ =4x^2-4x^2-6x+6-1= \\ = -6x+5[/tex]
[tex]x(x-2)= x^{2} -2x\\
2(x-1)^{2}=2(x^{2}-2x+1)=2x^{2}-4x+2\\
(x-1)(x+1)=x^{2}-1\\
-4(x^{2}-1)=-4x^{2}+4\\
E(x)=x^{2}-2x+2x^{2}-4x+2+x^{2}-1-4x^{2}+4=-6x+5[/tex]