15 3/28 - (4 11/28 + y) = 7-1 9/28
Раскроем скобки
3^2 x 10^4 x 7 x 10^-5
получаем
9 х 7 х 10^4 x 10^-5
63 x 10^-1
ответ 6.3
А)=(14/30+7/30+24/30)/(2-2/6-3/6)=(45/30)/1 1/6)=(45/30)/ (7/6) = 45/30 х 6/7 =45/5 х 1/7 = 45/7 = 6 3/7
б) = (5/30+3/30+ 2/30)/ (36/60-20/30-15/60)=(10/30) /(1/60)=10/30 х 60/1 = 10/1 х 2/1 = 20
11/36*17-5*11/36=11/36*(17-5)=11/36*12=11/3=9 2/3