What is the inverse of the function f(x) x-9?

Answer 1

Unfortunately, the rubbish browser used by Answers.com for posting questions is incapable of accepting mathematical symbols. This means that we cannot see the mathematically critical parts of the question. We are, therefore unable to determine what exactly the question is about and so cannot necessarily give a proper answer to your question.

If your question was about f(x) = x - 9, then the inverse function is g(x) = x + 9.

Answer 2

In general, you can calculate the inverse function as follows. Let's assume your function is f(x) = x - 9. Write this as:y = x - 9

Solving this for "x" will give you the inverse function (in which you would then have to exchange "y" and "x").