Ответ:
Пошаговое объяснение:
a) 8/9 * 3/4 - (5/6 - 1/4) = 2/3 - (10/12 -3/12) = 2/3 - 7/12 = 8/12 - 7/12 = 1/12
б) 3/5 + 4/5 * 3/7 + 6/7 = 3/5 + 12/35 + 6/7 = 21/35 + 12/35 + 30/35 = 63/35 = 9/5 = 1 4/5
в) (2/5 - 2/7) : 2/7 * 2/5 = (14/35 - 10/35) : 2/7 * 2/5 = 14/35 : 2/7 * 2/5 = 14/35 * 7/2 * 2/5 = 7/5 * 2/5 = 14/25
г) (5/6 - 3/10) : (3/10 + 2/15) = (25/30 - 9/30) : (9/30 + 4/30) = 16/30 : 13/30 = 16/30 * 30/13 = 16/13 = 1 3/13