a-1分之2a+2除以（a+1）- a方-2a+1分之a方-1
问题描述：
a-1分之2a+2除以（a+1）- a方-2a+1分之a方-1
答
原式=[2(a+1)/(a-1)]÷(a+1)-(a+1)(a-1)/(a-1)²
=2/(a-1)-(a+1)/(a-1)
=(2-a-1)/(a-1)
=(1-a)/(a-1)
=-(a-1)/(a-1)
=-1