80.5 -( y - 9 3/4 ) =28 5/6
У-9 3/4=80 5/10-28 5/6 у-9 3/4=80 15/30-28 25/30 у-9 3/4= 79 45/30-28 25/30 у-9 3/4=51 20/30=51 2/3 у=51 2/3-9 3/4 у=51 8/12-9 12/12 у=51 8/12-10 у=41 8/12=41 2/3