6 - (2,2х - 1 1/7) * 1 1/6 = 5,5
(2,2х - 1 1/7) * 1 1/6 = 6 - 5,5
(2,2х - 8/7) * 7/6 = 0,5
2,2х - 8/7 = 0,5 : 7/6
2,2х - 8/7 = 0,5 * 6/7
2,2х - 8/7 = (0,5*6)/7
2,2х - 8/7 = 3/7
2,2х = 3/7 + 8/7
11/5х = 11/7
х = 11/7 : 11/5
х = 11/7 * 5/11
х = 5/7
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Проверка: 6 - (11/5 * 5/7 - 8/7) * 7/6 = 5,5
6 - (11/7 - 8/7) * 7/6 = 5,5
6 - 3/7 * 7/6 = 5,5
6 - 3/6 = 5,5
6 - 0,5 = 5,5
5,5 = 5,5
Пояснения:
1 целая 1/7 = 7/7 + 1/7 = 8/7
1 целая 1/6 = 6/6 + 1/6 = 7/6
2,2 = 22/10 = 11/5 - сократили на 2
3/6 = 1/2 = 0,5 - сократили на 3