计算:2x/(x-2)(x+1)÷(1－x/x+1)-x²+2x/x²-4?

2x/(x-2)(x+1)÷(1－x/x+1)-x²+2x/x²-4?
=2x/(x-2)(x+1)×(x+1)/(1-x)-x(x+2)/(x+2)(x-2)
=2x/(x-2)(1-x)-x/(x-2)
=x/(x-2)×((2-1+x)/(1-x))
=x(x+1)/(x-2)(1-x);
如果本题有什么不明白可以追问,2x/(x-2)(x+1)×(x+1)/(1-x)-x(x+2)/(x+2)(x-2)这一步你弄错了啦2x/(x-2)(x+1)÷(1－x/x+1)-x²+2x/x²-4中“（1-x/x+1）”不是整体，有俩项1是以项，x/x+1是以项额。。。2x/(x-2)(x+1)÷(1－x/x+1)-x²+2x/x²-4=2x/(x-2)(x+1)÷(1/(x+1))-x(x+2)/(x+2)(x-2)=2x/(x-2)(x+1)×(x+1)-x/(x-2)=2x/(x-2)-x/(x-2)=x/(x-2)