To solve this equation, we need to combine like terms and simplify both sides of the equation.

Starting with the equation:

8х - 5/3 - 4х + 3/4 + 2х - 9/2 = -3

Combine the x terms:

(8х - 4х + 2х) = 6х

Combine the constant terms:

(-5/3 + 3/4 - 9/2) = ( -20/12 + 9/12 - 54/12) = -65/12

Now the equation becomes:

6х - 65/12 = -3

To isolate the variable term, we will first add 65/12 to both sides:

6х = -3 + 65/12
6х = -36/12 + 65/12
6х = 29/12

Finally, divide by 6 to solve for x:

x = 29/72