9 5/13-(7 6/13-y)=2 3/13
9 5/13 - (7 6/13 - у ) = 2 3/13 9 5/13 - 7 6/13 + у = 2 3/13 у = 2 3/13 - 9 5/13 + 7 6/13 у = 4/13
7 6/13-у=9 5/13-2 3/13 7 6/13-у=7 2/13 у=7 6/13-7 2/13 у=4/13 Ответ:у=4/13.