Define "this". Classically that means solve for x. So, you need to get x on one side of equals sign by itself and then whatever is on the other side is the answer. Your function is equivalent to this:
A - Bx = 0
Where A and B are constants and x is the variable. First you get the x portion by itself by adding it to both sides (because its essentially negative now):
A = Bx
Then you divide both sides by whatever x is multiplied by:
A/B = x
That's your answer. Apply those 2 steps to your equation and you'll get it for yours.