Ответ:\(\frac9{28}\cdot8=\frac{72}{28}=\frac{18}{7}=2\frac47\).\(\frac7{24}\cdot16=\frac{112}{24}=\frac{14}{3}=4\frac23\).\(42\cdot\frac47=6\cdot4=24\).\(\frac6{19}\cdot57=6\cdot3=18\).