因为1/a有意义,所以a≠0,
因为a²-3a+1=0,所以a-3+1/a=0
所以a+1/a=3
因为a²-3a+1=0,所以1-3/a+1/a²=0
a²-3a+1+1-3/a+1/a²=0
a²+1/a²=9-2=7
(a-1/a)²=a²+1/a²-2=5
a-1/a= ± 根号5
a²-3a+1-1+3/a-1/a²=0
a²-1/a²=±3 根号5
(a²-1/a²)(a-1/a)= 15
因为a^2-3a+1=0,有a≠0,所以a-3+1/a=0,a+1/a=3
则(a^2-1/a^2)(a-1/a)
=(a+1/a)(a-1/a)^2
=3(a^2-2+1/a^2)
=3[(a+1/a)^2-4]
=3[3^2-4]
=15