Answer:
Y = (x + 3)(x - 4)(x + 1)^2
Y = (x^2 - x - 12)(x^2 + 2x + 1)
Y = x^4 + 2x^3 + x^2 - x^3 - 2x^2 - x - 12x^2 - 24x - 12
Y = x^4 + x^3 - 13x^2 - 25x - 12
