x²-3x-1=0则x显然不为0∴ x-3-1/x=0即 x-1/x=3∴ (x-1/x)²=9即 x²+1/x²-2=9∴ x²+1/x²=11（1）(x²+1/x²)²=x^4+1/x^4+2*(x^4)*(1/x^4)即 121=x^4+1/x^4+2∴ x^4+1/x^4=...