2) Вычислите: 1) \(\frac{10!}{11!}\); 2) \(\frac{25!}{23!\cdot5!}\); 3) \(\frac{7!\cdot6!}{8!\cdot4!}\).

1. \(\frac{10!}{11!}=\frac{10!}{11\cdot10!}=\frac{1}{11}.\)

2. \(\frac{25!}{23!\cdot5!}=\frac{24\cdot25}{5\cdot4\cdot3\cdot2\cdot1}=5.\)

3. \(\frac{7!\cdot6!}{8!\cdot4!}=\frac{6!}{8\cdot7\cdot6!}\cdot\frac{6!}{4!}=\frac{1}{56}\cdot30=\frac{15}{28}.\)

Ответ: 1) \(\frac{1}{11}\); 2) 5; 3) \(\frac{15}{28}\).