Вычислите: 1) \(-3\frac{4}{5}\cdot\frac{15}{57}\cdot(-24)\); 2) \(\frac{11}{27}\cdot\left(-2\frac{12}{21}\right)\cdot(-21)\); 3) \(-3,5\cdot\left(-\frac{5}{7}\right)\); 4) \(-3\frac{1}{5}\cdot2,5\).

1. \(-3\frac{4}{5}=-\frac{19}{5}\), поэтому \[\left(-\frac{19}{5}\right)\cdot\frac{15}{57}\cdot(-24)=\frac{19\cdot3\cdot24}{57}=24.\]
2. \(-2\frac{12}{21}=-\frac{54}{21}=-\frac{18}{7}\), поэтому \[\frac{11}{27}\cdot\left(-\frac{18}{7}\right)\cdot(-21)=\frac{11\cdot18\cdot21}{27\cdot7}=22.\]
3. \[-3,5\cdot\left(-\frac{5}{7}\right)=\frac{7}{2}\cdot\frac{5}{7}=\frac{5}{2}=2,5.\]
4. \[-3\frac{1}{5}\cdot2,5=-\frac{16}{5}\cdot\frac{5}{2}=-8.\]

Ответ: 1) 24; 2) 22; 3) 2,5; 4) −8.