[MusicalityGuide] Additional Mathematics Form 4 Chapter 1 (Functions): How to do Inverse Functions

Let's say, you are given that f(x) = 3x + 2 and f-1(k) is 5, find k.

Draw out a relation, you can see that the object 5 links to image k, and that image k links to object 5. Now, use that info to find out the answer.

f(5)           = k
3(5) + 2    = k
k               = 15 + 2
k               = 17

See, easy as that! No need for long methods of finding inverse functions whatsoever!