Math Problem NEED HELP

[Bibtin Tex]

This is a problem i've been having with composition of functions, and i can't describe in simple words to google it, so I need some of your guys' help.

**THe small circle for "composed of" will be "~" since there is no key for it**

So..

if f(x)=x+4
and
g(x)=4x-1

find function h such that

a)f~h=g
b)h~f=g

so im ok with a) for the most part

i did :
f(h(x))=4x-1
h(x)+4=4x-1
h(x)=4x-5

and thats right, but my question is how do you do question B

if anyone can help can you explain to me why you do it that way, and a general rule or seomthing instead of this specific question as this is jsut an example

thanks

GFG!

[Phanuthier]

Ok what you have here is this:

h(x+4) = 4x - 1

You have to apply some function on (x+4) to make it (4x - 1) - how do you do that?

Multiply by 4, subtract the difference, and voila.

[Bibtin Tex]

Thx

Got my bro to help and he said the same thing