2) $$(y + 2)(y^2 - 2y + 4) = y^3 - 2y^2 + 4y + 2y^2 - 4y + 8 = y^3 + 8$$
3) $$(c - d^2)(c^2 + cd^2 + d^4) = c^3 + c^2d^2 + cd^4 - c^2d^2 - cd^4 - d^6 = c^3 - d^6$$
Ответ: 2) $$y^3 + 8$$, 3) $$c^3 - d^6$$