how do i factor

27x^3-21x^2y+108x^2-84yx

27x^3-21x^2y+108x^2-84yx

3x(9x^2 - 7xy + 36x - 28y)
3x(9x^2+36x - 7xy-28y)
3x(9x(x+4) - 7y(x+4))
3x(9x-7y)(x+4)