(15 5/12 + X) - 9 7/12 = 10 11/12
15 5/12 + X - 9 7/12 - 10 11/12 = 0
x = -5 5/12 + 9 7/12 + 10 11/12
x = 61/12 = 5 1/12
(15 5/12 + X) - 9 7/12 = 10 11/12
15 5/12 + X - 9 7/12 - 10 11/12 = 0
x = -5 5/12 + 9 7/12 + 10 11/12
x = 61/12 = 5 1/12