Question

If f (x) =1/9x-2 what is f1(x)?

Answer 1

`\large\boxed{f^(-1)(x)=9x+18}`

Explanation:

`f(x)=(1)/(9)x-2\to y=(1)/(9)x-2\\\\\text{Exchange x to y and vice versa}\\\\x=(1)/(9)y-2\\\\\text{solve for}\ y:\\\\(1)/(9)y-2=x\qquad\text{add 2 to both sides}\\\\(1)/(9)y=x+2\qquad\text{multiply both sides by 9}\\\\9\!\!\!\!\diagup^1\cdot(1)/(9\!\!\!\!\diagup_1)y=9x+(9)(2)\\\\y=9x+18`