x-1分之x的平方+1-x分之x
就是
x²/(x-1)+x/(1-x)
=x²/(x-1)-x/(x-1)
(x²-x)/(x-1)
=x(x-1)/(x-1)
=x
化简x-1分之x的平方+1-x分之x的结果是（x）