Let's find the inverse function:
1. replace f(x) with y
[tex]y=\frac{2x-9}{3}[/tex]2. Replace every x with a y and every y with an x:
[tex]x=\frac{2y-9}{3}[/tex]3. solve for y:
[tex]y=\frac{3x+9}{2}[/tex]4. replace y with f^-1(x)
[tex]f^{-1}(x)=\frac{3x+9}{2}[/tex]Now:
[tex]f^{-1}(3)=\frac{3(3)+9}{2}=\frac{9+9}{2}=\frac{18}{2}=9[/tex]since the functions are equal for x = 3 we can conclude that they have the same result
[tex]f(3)=f^{-1}(3)[/tex]