81. Решите уравнение: 1) 5/13 x = 2/13; 2) 8/9 x = 1; 3) 6/7 x = 24; 4) 7x = 3/4; 5) x : 3/11 = 22/27; 6) 3 3/5 : x = 9/35.

1. \(x=\frac{2}{13}:\frac{5}{13}=\frac{2}{5}\).
2. \(x=1:\frac{8}{9}=\frac{9}{8}\).
3. \(x=24:\frac{6}{7}=28\).
4. \(x=\frac{3}{4}:7=\frac{3}{28}\).
5. \(x=\frac{22}{27}\cdot\frac{3}{11}=\frac{2}{9}\).
6. \(x=3\frac{3}{5}:\frac{9}{35}=\frac{18}{5}\cdot\frac{35}{9}=14\).

Ответ: 1) \(x=\frac{2}{5}\); 2) \(x=\frac{9}{8}\); 3) \(x=28\); 4) \(x=\frac{3}{28}\); 5) \(x=\frac{2}{9}\); 6) \(x=14\).