a/a2-a+1=1/5
a^2-a+1=5a
a^2+1=6a
两边除a
a+1/a=6
两边平方
a^2+2+1/a^2=36
a^2+1/a^2=34
a^2/(a^2-a^2+1)
上下除a^2
=1/(a^2-1+1/a^2)
=1/(34-1)
=1/33