x^6-2*x^3+x^2+4=(x^3-1)^2+x^2+3
=((x-1)(x^2+x+1))^2+x^2+3
=(2(x-1)(x+1))^2+x^2+3
=4x^2+x^2+3
=5x+8
将x=(1+-sqrt(5))/2代入即可.