Пошаговое объяснение:

15 - 13 4/97) * ( 1 4/5 + 7/50) / (12 7/10 - 7) = 2/3

1) 15 - 13 4/97 = 14 97/97 - 13 4/97 = 1 93/97

2) 1 4/5 + 7/50 = 1 40/50 + 7/50 = 1 47/50

3) 12 7/10 - 7 = 5 7/10

4) 1 93/97 * 1 47/50 = 190/97 * 97/50 = 190 / 50 = 19/5

5) 19/5 : 5 7/10 = 19/5 : 57/10 = 19/5 * 10/57 = 2/3