x=2 y=12带入
8+8-2+m=12
m=-2
f(x)=x^3+2x^2-x-2
=x^3-x^2+3x^2-3x+2x-2
=x^2(x-1)+3x(x-1)+2(x-2)
=(x-1)(x^2+3x+2)
=(x-1)(x+1)(x+2)0
或
x-1
x=2 y=12带入
8+8-2+m=12
m=-2
f(x)=x^3+2x^2-x-2
=x^3-x^2+3x^2-3x+2x-2
=x^2(x-1)+3x(x-1)+2(x-2)
=(x-1)(x^2+3x+2)
=(x-1)(x+1)(x+2)0
或
x-1