1. Сократите дроби: 28/35; 8/12; 39/13.

1. \(\dfrac{28}{35}=\dfrac{28\mathbin{:}7}{35\mathbin{:}7}=\dfrac{4}{5}\).
2. \(\dfrac{8}{12}=\dfrac{8\mathbin{:}4}{12\mathbin{:}4}=\dfrac{2}{3}\).
3. \(\dfrac{39}{13}=3\).

Ответ: \(\dfrac{4}{5};\ \dfrac{2}{3};\ 3\).