x^3+6x^2+9x+4=0 则x³+1+6x²+9x+3=0则(x+1)(x²-x+1)+3(2x²+3x+1)=0则(x+1)(x²-x+1)+3(2x+1)(x+1)=0则(x+1)(x²-x+1+6x+3)=0则(x+1)(x²+5x+4)=0则(x+1)(x+1)(x+4)=0则(x+1)²(...