((15/28-11/36)*21/29-6 целых 6/7:(-16/21)):-16.5 = - 5/9
1) 15/28 - 11/36 = 135/252 - 77/252 = 58/252 = 29/126
2) 29/126 * 21/29 = 21/126 = 1/6
3) 6 6/7 : (- 16/21) = 48/7 * (- 21/16) = 3/1 * (- 3/1) = - 9
4) 1/6 - (-9) = 1/6 + 9 = 1/6 + 54/6 = 55/6 = 9 1/6
5) 9 1/6 : (- 16,5) = 55/6 : (- 16 5/10) = 55/6 : (- 165/10) = 55/6 * (-10/165) = 1/6 * (- 10/3) = - 10/18 = - 5/9