Make the f(x) a y: y =1/9x+2. Now subtract 2 from both sides. y-2 = 1/9x +2 -2, just so you can eliminate it on the right side of the equation. Then multiply both sides by 9 to leave the x alone. Now you have 9( y - 2) = 1/9x · 9.
Your final answers: 9y - 18 = x.the Switch the y and x variables: 9x - 18 = y.
Then, switch the y for f(x)^-1:
Answer: f(x)^-1= 9x - 18