Ответ:

7/15х - 3/5 = 26/25 : 13/15

7/15х - 3/5 = 26/25 × 15/13

7/15х - 3/5 = 6/5

7/15х = 6/5 + 3/5

7/15х = 9/5

х = 9/5 ÷ 7/15

х = 9/5 × 15/7

х = 27/7