1-(у-2)в кубе

1-(y-2)^3 = (1 -(y-2))*(1+y-2+(y-2)^2) = (1-y+2)*(y-1+y^2-4y+4) = (3-y)*(y^2-3y+3)
выполним проверку :
(3-y)*(y^2-3y+3) = 3*(y^2 -3y +3) - y*(y^2 -3y +3) = (3*y^2 -3*3y +3*3) - (y*y^2 -y*3y +y*3) = 3y^2-9y+9-y^3+3y^2-3y = 1 - (y^3+12y-6y^2-8) = 1-(y-2)^3
Ответ : (3-y)*(y^2-3y+3)