1 целая 1/7 = 8/7
3 целых 1/14 = 43/14
2 целых 5/7 = 19/7
1). 2 * 8/7 = 16/7
16/7 - 2х/1 - 43/14 = - 19/7
левую часть к общему знаменателю
32/14 - 28х/14 - 43/14 = (32-28х-43)/14 = (-11-28х)/14
(-11-28х)/14 = -19/7
пропорцией
(-11-28х) * (-7) = 14*19
77+196х = 266
196х = 266 - 77
196х = 189
х = 189/196 = 27/28