4. Решите уравнение: 1) $3x^3 - 108x = 0$; 2) $121x^3 - 22x^2 + x = 0$; 3) $x^3 - 2x^2 - 9x + 18 = 0$

1) $3x^3 - 108x = 0$; $3x(x^2 - 36) = 0$; $3x(x - 6)(x + 6) = 0$; $x = 0$, $x = 6$, $x = -6$. 2) $121x^3 - 22x^2 + x = 0$; $x(121x^2 - 22x + 1) = 0$; $x(11x - 1)^2 = 0$; $x = 0$, $x = \frac{1}{11}$. 3) $x^3 - 2x^2 - 9x + 18 = 0$; $x^2(x - 2) - 9(x - 2) = 0$; $(x - 2)(x^2 - 9) = 0$; $(x - 2)(x - 3)(x + 3) = 0$; $x = 2$, $x = 3$, $x = -3$.