Реши уравнение : 1 2/7 - (5-y)=9 1/7
1 2/7 - (5-y)=9 1/7 1 2/7 - 5 + y=9 1/7 -3 5/7 + y = 9 1/7 y = 9 1/7 + 3 5/7 y = 12 6/7