12. Выполните действия: 3-2 - 6-3 5(5d+1) 6(5d+1)

12. $$ \frac{3d-2}{5(5d+1)} - \frac{6d-3}{6(5d+1)} = \frac{6(3d-2) - 5(6d-3)}{30(5d+1)} = \frac{18d - 12 - 30d+15}{30(5d+1)} = \frac{-12d + 3}{30(5d+1)} = \frac{-4d+1}{10(5d+1)} $$

Ответ: $$ \frac{-4d+1}{10(5d+1)} $$