立方根?是x³+kx+6设x³+kx+6=A(x+2)则x-2时,x+2=0所以右边为0则左边也是0所以x=-2x³+kx+6=-8-2k+6=0k=-1x³+kx+6=x³+2x²-2x²-4x+4x+kx+6=x²(x+2)-2x(x+2)+(k+4)x+2(k+4)-2(k+...