\[3x² + 16x + 5 = 0\]
\[\left\{ \begin{matrix} x_{1} + x_{2} = - \frac{16}{3} \\ x_{1} \cdot x_{2} = \frac{5}{3}\text{\ \ \ \ \ \ \ } \\ \end{matrix} \right.\ \]
\[\Longrightarrow x_{1} = - 5;\ \ x_{2} = - \frac{1}{3}.\]