\[8m + 3n + 1\]
\[m = - 6,5;\ \ n = 4\frac{2}{3}:\]
\[8 \cdot ( - 6,5) + 3 \cdot 4\frac{2}{3} + 1 =\]
\[= - 52 + 3 \cdot \frac{14}{3} + 1 =\]
\[= - 52 + 14 + 1 = - 37.\]