\[ 7(x - 4) - 7 = 8(x - 4) \]
\[ 7x - 28 - 7 = 8x - 32 \]
\[ 7x - 35 = 8x - 32 \]
\[ -35 + 32 = 8x - 7x \]
\[ -3 = x \]
Ответ: x = -3