First, distribute the negative sign on the left side of the equation:

12 - 4x + 18 = 36 + 4x + 18 - 6x

Combine like terms on both sides:

30 - 4x = 54 - 2x

Next, isolate x on one side of the equation. Add 4x to both sides:

30 = 54 + 2x

Subtract 54 from both sides:

-24 = 2x

Finally, divide by 2 to solve for x:

x = -12

Therefore, the solution to the equation is x = -12.