[tex] \frac{1}{7} - 3( \frac{3}{7} n - \frac{2}{7}) \\ \\ \frac{1}{7} - 3( \frac{3n}{7} - \frac{2}{7} ) \\ \\ \frac{1}{7} - 3 \times \frac{3n - 2}{7} \\ \\ \frac{1}{7} - \frac{3(3n - 2)}{7} \\ \\ \frac{1-3(3n - 2)}{7} \\ \\ \frac{1-9n+6}{7} \\ \\ \frac{-9n + 7}{7} \\ \\ 1 - \frac{9n}{7} \\ \\ [/tex]
The final result is: 1 - 9n/7.
