\[26 - 4x = 12x - 7 \cdot (x + 4)\]
\[26 - 4x = 12x - 7x - 28\]
\[- 4x - 12x + 7x = - 28 - 26\]
\[- 9x = - 54\]
\[x = 6.\]
\[Ответ:при\ x = 6.\ \]