Question

(y-1)*(y-3)*(y-2)*(y-4)

Answer 1

$(y-1)(y-3)(y-2)(y-4)=(y^2-y-3y+3)(y^2-2y-4y+8)=\\=(y^2-4y+3)(y^2-6y+8)=\\=y^4-4y^3+3y^2-6y^3+24y^2-18y+8y^2-32y+24=\\=y^4-10y^3+35y^2-50y+24$