Запишите множество корней уравнения: (х + 3)(х^2 - 9) = 0.

\[(x + 3)\left( x^{2} - 9 \right) = 0\]

\[(x + 3)(x - 3)(x + 3) = 0\]

\[(x + 3)^{2}(x - 3) = 0\]

\[(x + 3)^{2} = 0\ \ \ \ \ \ \ \ \ \ x - 3 = 0\]

\[x + 3 = 0\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = 3\]

\[x = - 3\]

\[Ответ:\ x = \{ - 3;3\}.\]