1. ## function

f(x) = 5(2+x) and g(x) = x/5 +7 which maps R into R

$find f^{-1}x = x$

i know how to find $find f^{-1}x$ but am not sure what to so after that.

$f^{-1}x$=
y = x\5 -2

2. It looks like you are done. I don't see anything else you are supposed to do unless there is more to the question you didn't post. Do you need to find the inverse of g(x) too?

3. Originally Posted by dwsmith
It looks like you are done. I don't see anything else you are supposed to do unless there is more to the question you didn't post. Do you need to find the inverse of g(x) too?
ok i will post the question in order..

1. find $f^{-1} x$

2.determine the value of x which $f^{-1} x=x$

4. $\displaystyle f^{-1}(f(x))=x$

5. Could you show me how that is done. Am afraId I may interpret it the wrong way. Thanks.

6. $\displaystyle f^{-1}(5(2+x))=\frac{5(2+x)}{5}-2=\cdots$

7. Ok thanks alot

8. Since you had already determined that [tex]f^{-1}(x)= \frac{x}{5}- 2, determining x such that $f^{-1}(x)= x$ just means solving $\frac{x}{5}- 2= x$.