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:
![](https://i0.wp.com/pwntestprep.com/wp-content/uploads/2020/07/image-2.png?resize=340%2C72&ssl=1)
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 :