[tex]\displaystyle\it\\E(x)=\Bigg(\frac{1}{x^2-x}-\frac{1}{x^2+x}\Bigg)\cdot\frac{x^3-x}{x+2}.\\E(x)=\Bigg(\frac{1}{x(x-1)}-\frac{1}{x(x+1)}\Bigg)\cdot\frac{x(x^2-1)}{x+2}.\\E(x)=\Bigg(\frac {x+1}{(x-1)x(x+1)}-\frac{x-1}{(x-1)x(x+1)}\Bigg)\cdot \frac{x(x^2-1)}{x+2}.\\E(x)=\Bigg( \frac{2}{(x-1)x(x+1)}\Bigg)\cdot\frac{(x-1)x(x+1)}{x+2}.\\\boxed{\it E(x)=\frac{2}{x+2},~\forall~x\in\left\{-2,-1,0,1\right\}}.[/tex]
