\[x^{2} + 4x + q = 0\]
\[x_{1} - x_{2} = 8\]
\[x_{1} + x_{2} = - 4\]
\[x_{1} = - 4 - x_{2}\]
\[- 4 - x_{2} - x_{2} = 8\]
\[- 2x_{2} = 8 + 4\]
\[- 2x_{2} = 12\]
\[x_{2} = - 6.\]
\[x_{1} = - 4 - 6 = - 10.\]
\[q = x_{1} \cdot x_{2} = 6 \cdot 10 = 60.\]
\[Ответ:q = 60.\]