9*5/13-(7*6/13-у)=2*3/13
9 5/13-(7 6/13-у)=2 3/139 5/13-7 6/13+у=2 3/131 12/13+y=2 3/13y=2 3/13-1 12/13y= 4/13Ответ: 4/13