Question

What is the inverse of the function f(x) = 1/9x +2

Answer 1

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