Пошаговое объяснение:
8:10 2/3 = 8: 32/3 = 3/4
9 5/7 : 1 23/28 = 68/7 : 51/28 = (68*28)/(7*51) = (4*17*4*7)/(7*3*17) =16/3 = 5 1/3
1 2/15 : (3 7/9 - 2 3/7 ) = 17/15 : (34/9 + 17/7) = 17/15 : ((238+153)/63) = 17/15 : 391/63 = 17*63/15*391 = 21/5*23 = 21/115
