(3 5/6 - х) + 3 3/21 = 7 12/14;
Найдем х.
3 5/6 - x + 3 1/7 = 7 6/7;
-x = 7 6/7 - 3 1/7 - 3 5/6;
-x = 4 5/7 - 3 5/6;
x = 3 5/6 - 4 5/7;
x = -1 + 5/6 - 5/7;
x = -42/42 + 35/42 - 30/42;
x = -42/42 + 5/42;
x = -37/42.
(3 5/6 - х) + 3 3/21 = 7 12/14;
Найдем х.
3 5/6 - x + 3 1/7 = 7 6/7;
-x = 7 6/7 - 3 1/7 - 3 5/6;
-x = 4 5/7 - 3 5/6;
x = 3 5/6 - 4 5/7;
x = -1 + 5/6 - 5/7;
x = -42/42 + 35/42 - 30/42;
x = -42/42 + 5/42;
x = -37/42.