6 5/27 - (х - 1 2/9) = 3 20/81
х - 1 2/9 = 6 5/27 - 3 20/81
х - 1 2/9 = 6 15/81 - 3 20/81
х - 1 2/9 = 2 76/81
х = 2 76/81 + 1 2/9
х = 2 76/81 + 1 18/81
х = 3 94/81
х = 4 13/81
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Проверка: 6 5/27 - (4 13/81 - 1 2/9) = 3 20/81
6 5/27 - (4 13/81 - 1 18/81) = 3 20/81
6 5/27 - 2 76/81 = 3 20/81
6 15/81 - 2 76/81 = 3 20/81 - верно