Question

先化简，在求值

{（1+（a+1分之a）}除以（1-（1-a分之3a²)乘以a-1分之1，其中a=-二分之三

Answer 1

[1+a/(a+1)]除以[1-3a^2/(1-a)]*1/(a-1)
=(2a+1)/(a+1)*[(a-1)/(3a^2+a-1)]*1/(a-1)
=(2a+1)/[(a+1)(3a^2+a-1)]
a=-3/2
=[2*(-3/2)+1]/{(1-3/2)*[3*(-3/2)^2+(-3/2)-1]}
=-2/[(-1/2)*(17/4)]
=16/17