x^4+3x^3-4x^2-11x^2-19x+30
=x^2(x+4)(x-1)-(11x+30)(x-1)
=(x-1)(x^2(x+4)-11x-30)
=(x-1)(x^3+4x^2-11x-30)
因式分解x^4+3x^3-15x^2-19x+30
x^4+3x^3-4x^2-11x^2-19x+30
=x^2(x+4)(x-1)-(11x+30)(x-1)
=(x-1)(x^2(x+4)-11x-30)
=(x-1)(x^3+4x^2-11x-30)