x的平方-13x+1=0x+1/x=13 (0)(0)两边平方x^2+2+1/x^2=169x^2+1/x^2=167 (1)(1)两边再平方x^4+2+1/x^4=27889则 x^4+1/x^4=27887(1)-1x^2-1+1/x^2=166 (2)(0)*(2)x^3+1/x^3=2158