Question

If f -1(x) = (6/5)x - 9, find f (x).

Answer 1

Step-by-step explanation:

The equation is given below as

`f^(-1)(x)=(6)/(5)(x)-9`

Concept:

make x, the subject of the formula

`\begin{gathered} f^(-1)(x)=(6)/(5)(x)-9 \\ y=(6)/(5)(x)-9 \\ y+9=(6)/(5)x \\ multiply\text{ through by 5} \\ 5y+45=6x \\ divide\text{ through by 6, we will have} \\ (5y)/(6)+(45)/(6)=(6x)/(6) \\ x=(5)/(6)(x+9) \end{gathered}`

Hence,

The final answer is

`f(x)=(5)/(6)(x+9)`

The FIRST OPTION is the correct answer