Question

3次一元方程、、 2x^3-6x+4=0求解、、、

Answer 1

2x³-6x+4=0

x³-3x+2=0

显然x=1是方程的解,所以想办法分解出x-1

x³-1-3x+3=0

(x-1)(x²+x+1)-3(x-1)=0

(x-1)(x²+x+1-3)=0

(x-1)(x²+x-2)=0

(x-1)(x-1)(x+2)=0

所以x=1或x=-2