x/x的平方-1 - 1/x+1 等于多少

问题描述:

x/x的平方-1 - 1/x+1 等于多少

原式=x/(x+1)(x-1)-1/(x+1)
=x/(x+1)(x-1)-(x-1)/(x+1)(x-1)
=(x-x+1)/(x+1)(x-1)
=1/(x+1)(x-1)