31/42-(y+9/42)=15/42
Ответ:
Пошаговое объяснение:
31/42-y-9/42=15/42
-y=15/42+9/42-31/42
-y=-7/42=-1/6
y=1/6
31/42-(y+9/42)=15/42 y+9/42=31/42-15/42 y+9/42=16/42 y=16/42-9/42 y=7/42 y=1/42