1)
6 5/27 - (x - 1 2/9) = 3 20/81
x - 1 2/9 = 6 5/27 - 3 20/81
x - 1 2/9 = 6 15/81 - 3 20/81
x - 1 2/9 = 5 96/81 - 3 20/81
x - 1 2/9 = 2 76/81
x = 2 76/81 + 1 2/9
x = 2 76/81 + 1 18/81
x = 3 94/81
x = 4 13/81
Ответ: 4 13/81
2)
9 9/28 - (4 5/21 - x) = 6 2/7
4 5/21 - x = 9 9/28 - 6 2/7
4 5/21 - x = 9 9/28 - 6 8/28
4 5/21 - x = 3 1/28
x = 4 5/21 - 3 1/28
x = 4 140/588 - 3 21/588
x = 1 119/588
x = 1 17/84
Ответ: 1 17/84
3)
3 5/36 - (1 31/54 - x) = 1 17/27
1 31/54 - x = 3 5/36 - 1 17/27
1 31/54 - x = 339/108 - 176/108
1 31/54 - x = 163/108
1 31/54 - x = 1 55/108
x = 1 31/54 - 1 55/108
x = 1 62/108 - 1 55/108
x = 7/108
Ответ: 7/108