Find the common denominator first.
-6(1/4x -2/3x + 5/6x)
-6(3/12x - 8/12x + 10/12x)
-6(3x * -5/12 + 10/12)
-6 (3x * 5/12)
-6 (15/12x)
-6 (1 3/12x)
-6(1 1/4x)
7.5x