Question

se considera expresia E(x)​

Answer 1

$E(x)=(x+1)^2+2(x+1)(x-2)+(x-2)^2=\\x^2+2x+1+2(x^2-x-2)+x^2-4x+4=\\x^2+2x+1+2x^2-2x-4+x^2-4x+4=\\4x^2-4x+1=(2x-1)^2 \ \forall x \in \mathbb{R}$