Решите уравнение: (6/7-y)+2/7=5/7.

\[\left( \frac{6}{7} - y \right) + \frac{2}{7} = \frac{5}{7}\]

\[\frac{6}{7} - y = \frac{5}{7} - \frac{2}{7}\]

\[\frac{6}{7} - y = \frac{3}{7}\]

\[y = \frac{6}{7} - \frac{3}{7}\]

\[y = \frac{3}{7}.\]

\[Ответ:y = \frac{3}{7}.\]