Suppose that g(x)=f^{-1}(x). If g(-15)=0, g(0)=3, g(4)=9, g(1) = 4, and g(9)=20, what is f(f(9))?
If (-15, 0) , ( 4 , 9) (0, 3) (1, 4) and ( 9.20) are on the inverse of f
Then
(0, - 15) (9, 4) (3, 0) (4, 1) and ( 20 , 9) are on f
So
f(9) = 4
And f (f(9)) = f(4) = 1
