a²-a-1=0a²=a+1a²-a-1=0a²-1=aa-1/a=1（a³-1）/a=(a-1)(a²+a+1)/a=(a-1)(a+1+a+1)/a=2(a-1)(a+1)/a=2(a²-1)/a=2(a-1/a)=2x1=2如果本题有什么不明白可以追问,