Решите уравнение: 2/3-(7/9-а)=1/3
2/3-(7/9-а)=1/37/9-а=2/3-1/37/9-а=1/3а=7/9-1/3а=4/9Проверка:2/3-(7/9-4/9)=1/32/3-1/3=1/31/3=1/3