1) (4 7/8:х-1 3/4) * 1 7/21=3 2/3 2) 3 15/17: (*-3 5/24) = 15/18+4 5/6

1) (4 7/8 : х - 1 3/4) * 1 7/21 = 3 2/3;

((4 * 8 + 7) / 8 : х - (1 * 4 + 3) / 4) * (1 * 21 + 7) / 21 = (3 * 3 + 2) / 3;

(39/8 : х - 7/4) * 28/21 = 11/3;

39/8 : х - 7/4 = 11/3 * 21/28;

39/8 : х = 11/4 + 7/4;

39/8 : х = 18/4;

х = 39/8 : 18/4 = 39/8 * 4/18 = (39 * 4) / (8 * 18) = 13 / (2 * 6) = 13/12.

2) 3 15/17 : (х - 3 5/24) = 15/18 + 4 5/6;

(3 * 17 + 15) / 17 : (х - (3 * 24 + 5) / 24) = 15/18 + (4 * 6 + 5) / 6;

66/17 : (х - 77/24) = 15/18 + 29/6;

66/17 : (х - 77/24) = 102/18;

х - 77/24 = 66/17 : 102/18;

х = 77/24 + 66/17 * 18/102 = 77/24 + 198/289 = 534072/6936 + 4752/6936 = 22451/289.