To solve this equation, we need to simplify both sides of the equation step by step.

Starting with the left side of the equation:

5/8 (4/5x - 1.6) + 0.75 (1/3 + 1 1/3)
= (5/8) (4/5x) - (5/8) 1.6 + (0.75) (1/3) + (0.75) (4/3)
= (5/8) * (4/5x) - 1 - (5/20) + (3/4)
= (1/2)x - 1 - 1/4 + 3/4
= (1/2)x + 1/2

Now, for the right side of the equation:

5 - 3x

Now we equate the two sides and solve for x:

(1/2)x + 1/2 = 5 - 3x
1/2x + 1/2 = 5 - 3x
1/2x + 3x = 5 - 1/2
5/2x = 9/2
x = 9/10

Therefore, the solution to the equation is x = 9/10.