# Thread: inverse function help !

1. ## inverse function help !

hi , im stuck on this question i can do most of it but not the last bit:

heres the question:

f(x) = (x+10) / (x-8) (where x isnt 8)

1) find a positive integer p such that f(p) = p

2)find also f^-1(p) for the positive integer found in question 1

thanks

2. Originally Posted by mike--1988
hi , im stuck on this question i can do most of it but not the last bit:

heres the question:

f(x) = (x+10) / (x-8) (where x isnt 8)

1) find a positive integer p such that f(p) = p

2)find also f^-1(p) for the positive integer found in question 1

thanks
1) Solve $\frac{p+10}{p-8} = p$.

2) You should know that if $f(p) = p$ then $f^{-1} (p) = p$ since points on the line y = x get reflected onto themselves.