Question

（a+1分之a的2次方-a+1）除以a的2次方-1分之a

Answer 1

原式=[a²/(a+1)-(a-1)]×(a²-1)/a

=[a²-(a+1)(a-1)]/(a+1)×(a+1)(a-1)/a

=(a²-a²+1)/(a+1)×(a+1)(a-1)/a

=1/(a+1)×(a+1)(a-1)/a

=(a-1)/a