2) 21/5 · 3/7; 8) 6/5 : 4/11; 14) (5/22 − 8/11) · 11/5; 20) (2/5 + 13/15) · 6

1. \(\frac{21}{5}\cdot\frac{3}{7}=\frac{63}{35}=\frac{9}{5}\).
2. \(\frac{6}{5}:\frac{4}{11}=\frac{6}{5}\cdot\frac{11}{4}=\frac{33}{10}\).
3. \(\left(\frac{5}{22}-\frac{8}{11}\right)\cdot\frac{11}{5}=\left(\frac{5}{22}-\frac{16}{22}\right)\cdot\frac{11}{5}=\left(-\frac{11}{22}\right)\cdot\frac{11}{5}=-\frac12\cdot\frac{11}{5}=-\frac{11}{10}\).
4. \(\left(\frac25+\frac{13}{15}\right)\cdot6=\left(\frac6{15}+\frac{13}{15}\right)\cdot6=\frac{19}{15}\cdot6=\frac{38}{5}\).

Ответ: 2) \(\frac95\); 8) \(\frac{33}{10}\); 14) \(-\frac{11}{10}\); 20) \(\frac{38}{5}\).