5/14a + - 2/5c + 1/8b -2/5c + 3/8b + 7/14 a

5/14a + 1/8b -2/5c + 3/8b -2/5c + 7/14a

= (5/14 + 7/14)a + (1/8 + 3/8)b + (-2/5 -2/5)c
= 12/14a + 4/8b + (-4/5)c
= 6/7a + 1/2b -4/5c