\[x = 6:\]
\[5 \cdot (x - 2) - 4 \cdot (3 + x) = 2 + ax\]
\[5 \cdot (6 - 2) - 4 \cdot (3 + 6) = 2 + 6a\]
\[20 - 36 = 2 + 6a\]
\[6a = - 16 - 2\]
\[6a = - 18\]
\[a = - 3.\]
\[Ответ:при\ a = - 3.\]