C. Adding 18 to both sides isolates the variable term.
Your end goal is to isolate “x” which is a variable. However, the variable is multiplied by 6 and is “6x” making it a variable term. You must first isolate the variable term before you can isolate the variable itself. So step 1 is to add 18 to both sides (cancelling it out on the left side of the equals sign), thus isolating the variable term.
The answer is B. because if you make an equation in the form y=mx+b then you can solve the equation by inputting x where x goes in the equation and solving. BTW the equation would be y=2x-1
