Question

Помогите
$frac{x^2-1}{1-x^3} - frac{x^2}{x^2+x+1}$

Answer 1

(x-1)(x+1)/[(1-x)(1+x+x²)]-x²/(x²+x+1)=-(x+1)/(1+x+x²)-x²/(1+x+x²)=
=-(x+1+x²)/(1+x+x²)=-1