计算a²/(a-1)-a-1的值

问题描述:

计算a²/(a-1)-a-1的值

=a²/(a-1)-(a+1)
=a²/(a-1)-(a+1)(a-1)/(a-1)
=a²/(a-1)-(a²-1)/(a-1)
=[a²-(a²-1)]/(a-1)
=1/(a-1)