=(x(x+1)) /(2-x-1) -((2-2x+4x))/ ((1-x)(x+1))=x(x+1)^2) /((1-x)(x+1)) -
-(2+2x)/((1-x)(x+1))+3*(1-x^2) /((1-x)(x+1))=(x^3+2x^2+x-2-2x+3-3x^2) / (1-x^2)=(x^3-x^2-x+1) /(1-x^2)=((x^2(x-1)-(x-1)) /((1-x)(1+x))=((x-1)(x^2-1)) /
/((1-x)(1+x))=-((x-1)(1-x^2)) /(1-x^2)=1-x