解方程x^3+6x^2+9x+4=0
问题描述：
解方程x^3+6x^2+9x+4=0
答
X(X^2+6X+9)+4=0
X(X+3)^2+4=0
X(X+3)^2=-4
X=-2或-4因为(x+3)^2总为正数
则x=-4
答
x^3+6x^2+9x+4
=x³+1+6x²+9x+3
=（x+1）（x²-x+1）+3（2x²+3x+1）
=(x+1)(x²-x+1)+3(2x+1)(x+1)
=(x+1)(x²-x+1+6x+3)
=(x+1)(x²+5x+4)
=(x+1)(x+1)(x+4)
=(x+1)²(x+4)=0
所以x+1=0或x+4=0,解得x=-1或x=-4
答
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(...