设x^3+kx^2+x+1 = (x-1)f(x) f(x)为x表达式
x=1时,式子两边值为0
所以
1+k+1+1=0
k=-3
x^3-3x^2+x+1
=x^3-x^2-2x^2+2x-x+1
=x^2(x-1)-2x(x-1)-1
=(x^2-2x-1)(x-1)
如果要求实数范围内分解因式的话
=(x-1-√2)(x+1+√2)(x-1)