First, let's simplify the equation:

136.5 - x = 5.4 / 0.12

Now, let's divide 5.4 by 0.12:

5.4 / 0.12 = 45

So, the equation becomes:

136.5 - x = 45

Now, let's solve for x:

x = 136.5 - 45
x = 91.5

Therefore, the solution to the equation is x = 91.5.