\[34 - 4x + x(3x + 4) = 2 \cdot \frac{109}{2}\]
\[34 - 4x + 3x^{2} + 4x = 109\]
\[3x^{2} = 109 - 34\]
\[3x^{2} = 75\]
\[x^{2} = 25\]
\[x = \pm 5.\]
\[Ответ:\ \pm 5.\]