35/6-(17/6+а)=1 1/12
35/6-17/6+а=1 1/12
18/6+а=1 1/12
3+а=1 1/12
а= 1 1/12 -3= 1 1/12-2 12/12=-1 11/12
35/6-(17/6+а)=11/12
17/6+а= 35/6-11/12
17/6+а= 59/12
а= 59/12-17/6
а= 25/12 или 2 1/12
