Ответ:

Пошаговое объяснение:

1) 3. 4/15 - 2. 11/21 =

3. 28/105 - 2. 55/105 =

2. 133/105 - 2. 55/105 =

78/105 = 26/35

2) 26/35 : 15,6 = 26/35 :

15. 6/10 = 26/35 : 15. 3/5 = 26/35 : 78/5 =

26/35 * 5/78 = 1/7 * 1/3 =

1/21

3) 1/21 - 14 = 1/21 - 13. 21/21 = -13. 20/21