Ответ:
Пошаговое объяснение:
870.
1) x = 3/5 - 1/8
x = 24/40 - 5/40
x = 19/40
2) x = 5/12 - 1/3
x = 5/12 - 4/12
x = 1/12
3) x = 1/5 + 3/20
x = 4/20 + 3/20
x = 7/20
4) x = 4/21 + 3/7
x = 4/21 + 9/21
x = 13/21
5) x = 4/5 - 1/6
x = 24/30 - 5/30
x = 19/30
6) x = 5/8 - 1/3
x = 15/24 - 8/24
x = 7/24
871.
1) 8/18 - 8/27 = 24/54 - 16/54 = 8/54 = 4/27
2) 7/16 - 5/24 = 21/48 - 10/48 = 11/48
3) 2/11 - 1/12 = 24/132 - 11/132 = 13/132
4) 12/13 - 15/26 = 24/26 - 15/26 = 9/26
5) 9/28 - 11/35 = 45/140 - 44/140 = 1/140
6) 39/40 - 19/28 = 273/280 - 190/280 = 83/280