Ответ:\(\frac{9}{35}\cdot8=\frac{72}{35}=2\frac{2}{35}\).\(\frac{7}{24}\cdot16=\frac{7\cdot2}{3}=\frac{14}{3}=4\frac{2}{3}\).\(42\cdot\frac{4}{7}=6\cdot4=24\).\(\frac{6}{19}\cdot57=6\cdot3=18\).