\[\frac{3x + 1}{10} - \frac{8x - 3}{7} = - 2\ \ \ | \cdot 70\]
\[7(3x + 1) - 10(8x - 3) = - 140\]
\[21x + 7 - 80x + 30 = - 140\]
\[- 59x = - 140 - 37\]
\[- 59x = - 177\]
\[x = 3.\]