(1 1/4x - 5 1/6) - (5/8x + 1 1/3)
1 1/4x - 5 1/6 - 5/8x - 1 1/3
(1 1/4x - 5/8x) - (5 1/6 + 1 1/3)
(1 1/4 - 5/8)x - (5 1/6 + 1 1/3)
*note
1 1/4 = 5/4 = 10/8
5 1/6 = 31/6
1 1/3 = 4/3 = 8/6
*thus your equation can now be written using additive/subtractive components with common denominators
(10/8 - 5/8)x - (31/6 + 8/6)
(5/8)x - (39/6)
ANSWER:
5/8x - 39/6
5/8x - 6 3/6
5/8x - 6 1/2