DDmitrySj 1) (7/15 + 3/10) = 14/30 + 9/30 = 23/30
2) (7/19-30/57) = 21/57 - 30/57 = -9/57
3) 23/30 * 2 14/13 = 2 14/39
4)2 14/39 + 16/57 = 2 158/247
5) 2 158/247 : -9/57= -16 28/39

Ответ -16 целых 28/39