a^3 + b^3 = (a + b)(a^2 - ab + b^2)
u + 8 = (u^1/3)^3 + 2^3 = (u^1/3 + 2) (u^2/3 - 2u^1/3 + 4) = (∛u + 2)(∛u² - 2∛u + 4)
(u + 8)/(u^2/3 - 2∛u + 4) = ∛u + 2
заработали
