\[ax < 8x - 7\]
\[ax - 8x < - 7\]
\[(a - 8)x < - 7\]
\[x < - \frac{7}{a - 8}\]
\[Нет\ решения\ \]
\[при\ a - 8 = 0 \Longrightarrow a = 8.\]
\[Ответ:\ \ при\ a = 8.\]