а = 130/300 + 90/300а = 220/300а = 11/15
2/18 + c = 1 - 12/182/18 + c = 1 - 2/32/18 + c = 1/3c = 1/3 - 2/18c = 6/18 - 2/18c = 4/18c = 2/9
а = 130/300 + 90/300
а = 220/300
а = 11/15
2/18 + c = 1 - 12/18
2/18 + c = 1 - 2/3
2/18 + c = 1/3
c = 1/3 - 2/18
c = 6/18 - 2/18
c = 4/18
c = 2/9