1)8 целых 7/9-x=3 целых 5/6() 2) (x-5/6)+11/18=19/24

8 7/9 - х = 3 5/6
х = 8 7/9 - 3 5/6
х = 5 + (7/9 - 5/6) = 8 + ( 14/18 - 15/18)  = 8 - 1/18
х = 7целых 17/18

х - 5/6 + 11/18 = 19/24
х - (15/18 + 11/18) = 19/24
х - 4/18 = 19/24
х = 19/24 + 4/18 = 57/72 + 16/72
х = 73/72
х = 1 целая 1/72.