(x + 6)(x² - 8x + 16) = 9(4 - x)
(x + 6)(x - 4)² - 9(4 - x) = 0
(x + 6)(x - 4)² + 9(x - 4) = 0
(x - 4)[(x + 6)(x - 4) + 9] = 0
(x - 4)(x² - 4x + 6x - 24 + 9) = 0
(x - 4)(x² + 2x - 15) = 0
(x - 4)(x + 5)(x - 3) = 0
x - 4 = 0 или x + 5 = 0 или x - 3 = 0
x₁ = 4 x₂ = - 5 x₃ = 3
Ответ : - 5 ; 3 ; 4