x^3 -9 =9x -x^2 解方程

x^3 -9 =9x -x^2 解方程
x^3 -9 =9x -x^2 解方程

x^3 -9 =9x -x^2 解方程
x³-9=9x-x²
x³+x²-9x-9=0
x²(x+1)-9(x+1)=0
(x+1)(x²-9)=0
(x+1)(x+3)(x-3)=0
x=-1或x=-3或x=3

x^3 -9 =9x -x^2
x^3 -9x=9-x^2
x(x^2 -9)=-(x^2 -9)
x=-1 或者x=±3

x^3 +x^2- 9x-9 =0
x^2(x+1)-9(x+1)=0
(x+1)(x^2-9)=0
(x+1)(x+3)(x-3)=0
x1=-1
x2=-3
x3=3

x^3 -9 =9x -x^2
x^3+x^2-9x-9=0
x^2(x+1)-9(x+1)=0
(x+1)(x^2-9)=0
(x+1)(x+3)(x-3)=0
x+1=0,x+3=0,x-3=0
x=-1,x=-3,x=3