Question

a²-1分之2a+1×a²-a分之a²-2a+1减a+1分之1 其中a=-2分之2

Answer 1

(2a+1)/(a²-1)×(a²-2a+1)/(a²-a)-1/(a+1)

=(2a+1)/[(a-1)(a+1)]×(a-1)²/[a(a-1)]-1/(a+1)

=(2a+1)/[a(a+1)]-1/(a+1)

=(2a+1-a)/[a(a+1)]

=1/a

当a=-2/2时,

原式=1/(-2/2)=-1

注意：手写的时候,分子分母最外层的括号要去掉.