Решите уравнение: a+0,1a+2/7*a=1.

\[a + 0,1a + \frac{2}{7}a = 1\]

\[a + \frac{1}{10}a + \frac{2}{7}a = 70\ \ \ \ | \cdot 70\]

\[70a + 7a + 20a = 70\]

\[97a = 70\]

\[a = \frac{70}{97}.\]