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