How do you solve #0.06x + 0.03(4000 - x) = 153#?
Start by distributing 0.03.
Next, move the equation around to get numbers on one side and letters on the other. Don't forget to change their signs when moving them onto their opposite sides (ie: negative to positive or positive to negative). In this case, I had to move 120 over to the right side of the equation and change its sign to negative.
Simplify your equation on both sides.
Divide by 0.03 to get x by itself.
You now have your final answer! :)