x^5-4*x^4-4*x+16/(x^2-2)*(x^2-5*x+4)
(x^5-4x^4-4x+16)/(x^2-2)(x-1)(x-4)=(x^3-4x^2+2x-8)/(x-1)(x-4)=(x-4)(x^2+2)/(x-4)(x-1)=(x^2+2)/(x-1)