Because f(x)=y, begin by changing f(x) to the y-value, getting y=2x-4. Because we are determining the inverse of the equation, this means that the x and y-value should be switched, getting x=2y-4. Now that we're trying to isolate y, move 4 to the other side to get x+4=2y. Divide by 2 on both sides to get y=x+2. Now, we substitute y for f(x), but this time we put (x), because it's the inverse of f(x).
