\[(5x - 3) + (7x - 4) = 8 - (15 - 11x)\]
\[5x - 3 + 7x - 4 = 8 - 15 + 11x\]
\[12x - 11x = - 7 + 7\]
\[x = 0.\]
\[Ответ:x = 0.\]