\[(x - 3)(x + 12) = 0\]
\[x - 3 = 0\ \ \ \ \ \ \ \ x + 12 = 0\]
\[x = 3\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - 12\]
\[Ответ:\ \ x = 3\ \ \ и\ \ \ x = - 12.\]