To solve for x, we first need to isolate the variable on one side of the equation.

First, let's simplify the equation:

9/2 + 0.75x = 3

To get rid of the fraction, we can multiply every term by 2:

2(9/2) + 2(0.75x) = 2(3)
9 + 1.5x = 6

Now, let's isolate the variable x by subtracting 9 from both sides:

1.5x = 6 - 9
1.5x = -3

Finally, divide by 1.5 to solve for x:

x = -3 / 1.5
x = -2

Therefore, the solution to the equation is x = -2.