50/14 - (у + 2) = 9/14
50/14 - у - 2 = 9/14
50/14 - у - 28/14 = 9/14
22/14 - у = 9/14
1) 22/14 - 1 3/14 - 9/14 = 22/14 - 17/14 - 9/14 = - 4/14 = - 2/7
2) 22/14 - 13/14 - 9/14 = 0
3) 22/14 - 1/14 - 9/14 = 12/14 = 6/7
4) 22/14 - 1 1/14 - 9/14 = 22/14 - 15/14 - 9/14 = - 2/14