Ответ:

Пошаговое объяснение:

18/30 - х = 4/30 + 6/30

18/30 - х = 10/30

х = 18/30 - 10/30

х = 8/30

х = 4/15

(13/67 + 6/67) - х = 9/67

19/67 - х = 9/67

х = 19/67 - 9/67

х = 10/67

10/15 + (5/15 - х) = 14/15

5/15 - х = 14/15 - 10/15

5/15 - х = 4/15

х = 5/15 - 4/15

х = 1/15