13.5x - 11.7 = 7.8x + 5.4

To solve for x, we need to isolate x on one side of the equation. Let's first combine the x terms on one side:

13.5x - 7.8x = 5.4 + 11.7
5.7x = 17.1

Now, divide by 5.7 on both sides to solve for x:

x = 17.1 / 5.7
x = 3

Therefore, the solution to the equation is x = 3.