3) x(x + 2)(6 - x) = 14 - x(x - 2)²;
x(6x - x² + 12 - 2x) = 14 - x(x² - 4x + 4)
6x² - x³ + 12x - 2x² = 14 - x³ + 4x² - 4x
4x² - x³ + 12x = 14 - x³ + 4x² - 4x
16x = 14
x = 14/16 = 7/8 = 0.875
Ответ: x = 0.875