№7. Сократи дроби: 6/8; 28/42; 65/91; 15/25; 36/54; 138/184; 21/35; 44/66; 287/369.

Делим числитель и знаменатель каждой дроби на их общий делитель:

1. \(\frac{6}{8}=\frac{6:2}{8:2}=\frac{3}{4}\);
2. \(\frac{28}{42}=\frac{28:14}{42:14}=\frac{2}{3}\);
3. \(\frac{65}{91}=\frac{65:13}{91:13}=\frac{5}{7}\);
4. \(\frac{15}{25}=\frac{15:5}{25:5}=\frac{3}{5}\);
5. \(\frac{36}{54}=\frac{36:18}{54:18}=\frac{2}{3}\);
6. \(\frac{138}{184}=\frac{138:46}{184:46}=\frac{3}{4}\);
7. \(\frac{21}{35}=\frac{21:7}{35:7}=\frac{3}{5}\);
8. \(\frac{44}{66}=\frac{44:22}{66:22}=\frac{2}{3}\);
9. \(\frac{287}{369}=\frac{287:41}{369:41}=\frac{7}{9}\).

Ответ: \(\frac{3}{4};\ \frac{2}{3};\ \frac{5}{7};\ \frac{3}{5};\ \frac{2}{3};\ \frac{3}{4};\ \frac{3}{5};\ \frac{2}{3};\ \frac{7}{9}\).