Algebra

We know that f(3) = 4, so we want the inside of f(2x/3) to equal 3. We notice that when we have x=9/2, then we have $y=\frac{5+f(3)}{11} = \frac{5+4}{11}$. 

This is easily solvable, so we get y=9/11. 

This means that the point (9/2, 9/11) has to be on the line. 

Thanks!