Solution
Start by substituting y for f(x). That's easier to handle.
y = (1/9)x + 2 Interchange the x and the y. Where you see an x put a y and where you see a y put an x.
x = (1/9)y + 2 Subtract 2 from both sides.
(x - 2) = (1/9)y + 2 - 2
(x - 2) = (1/9)y Multiply both sides by 9
9(x - 2) = (1/9)y * 9
9(x - 2) = y You can put the y on the left and the left over on the right.
y = 9(x - 2) Put f(x) back in
f(x) = 9(x - 2) This could be the answer. You could also remove the brackets.
y = 9x - 18