3x^2-x=1所以3x^2=x+16x^3=3x^2*2x=2x(x+1)=2x^2+2x所以6x^3+9x^2-(17/3)x+2005=2x^2+2x+9x^2-(17/3)x+2005=11x^2-(11/3)x+2005=(11/3)(3x^2-x)+2005=(11/3)*1+2005=6026/3