\[3 + x \leq 8x - (3x + 7)\]
\[3 + x \leq 8x - 3x - 7\]
\[x - 5x \leq - 7 - 3\]
\[- 4x \leq - 10\]
\[x \geq 2,5\]
\[Ответ:x \geq 2,5.\]