就一道,过程求完整:1.x³-2x²-4x+8=0

就一道,过程求完整:1.x³-2x²-4x+8=0
就一道,过程求完整:1.x³-2x²-4x+8=0

就一道,过程求完整:1.x³-2x²-4x+8=0
x³-2x²-4x+8=0
x²(x-2)-4(x-2)=0
(x-2)(x²-4)=0
(x+2)(x-2)²=0
x=-2,x=2

=x²(x-2) -4(x-2)
=(x-2)(x²-4)
=(x+2)(x-2)²

x³-2x²-4x+8=0
(x³-4x)-2(x²-4)=0
x(x²-4)-2(x²-4)=0
(x-2)(x²-4)=0
(x-2)²(x+2)=0
∴x=2或x=-2