Hi! May you please explain how to find the function for f(x) for number 5 from the practice questions in the “functions” chapter? I saw the solution, which said to find f(5+3), and then I got the correct answer, but I wanted to see if there is a function that could be found (as I tried to find it but I found it incorrectly and got an incorrect answer).

Sure. Here’s the question for those following along:

As you note, the quick and dirty way to go is to set and solve for . If you really want to find , though, it can be done. Just think through everything that needs to happen to to turn it into !

First, it’s going to have to be multiplied by 10.

But , not .

So after you multiply by 10, subtract 26! That will land you right where you want to be. , so the function is .

Solve that for :