α是方程x2+x-1∕4=0的根,则α2+α=1/4
(α3-1) ∕(α5+α4-α3-α2)=(α-1)(α2+α+1)/α2(α+1)2(a-1)
=(α2+α+1) / α2(α+1)2
=(1/4+1)/(1/4)2
=20