\[\frac{x - 2}{3} = \frac{3x + 1}{7}\ \ \ \ \ \ \ \ \ \ \ | \cdot 21\]
\[7 \cdot (x - 2) = 3 \cdot (3x + 1)\]
\[7x - 14 = 9x + 3\]
\[7x - 9x = 3 + 14\]
\[- 2x = 17\]
\[x = - 8,5.\]