\[- \frac{1}{6}x^{2} - \frac{3}{2}x + 6 = 0\ \ \ | \cdot ( - 6)\]
\[x^{2} + 9x - 36 = 0\]
\[\left\{ \begin{matrix} x_{1} + x_{2} = - 9 \\ x_{1} \cdot x_{2} = - 36 \\ \end{matrix} \right.\ \]
\[x_{1} = - 12;\ \ x_{2} = 3:\]
\[\Longrightarrow - \frac{1}{6}x^{2} - \frac{3}{2}x + 6 =\]
\[= - \frac{1}{6} \cdot (x + 12)(x - 3).\]