\[9x² + 6x = 0\]
\[3x(3x + 2) = 0\]
\[x = 0\ \ или\ \ \ 3x = - 2\ \ \]
\[\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - \frac{2}{3}\]
\[Ответ:x = 0;x = - \frac{2}{3}.\]