Confirm that f and g are inverses by showing that f(g(x)) = x and g(f(x)) = x
f(x) = 9x + 3 and g(x) = Quantity x minus three divided by nine

Question

Confirm that f and g are inverses by showing that f(g(x)) = x and g(f(x)) = x
f(x) = 9x + 3 and g(x) = Quantity x minus three divided by nine

jenniferfournierr · Answer

@jtug6

zzr0ck3r · Answer

I have noticed you keep posting the same sort of questions and when people give you the steps you say you understand. But then you post the same question again. Can you show us what you think might be a good place to get started?

zzr0ck3r · Answer

Maybe refer back to older question.

jenniferfournierr · Answer

f(x-3/9)=9 (x-3/9)+3

jenniferfournierr · Answer

@zzr0ck3r

zzr0ck3r · Answer

right, the nines cancel and you are left with what?

faiqraees · Answer

The best way to prove is by inputting any value of x in the function of f(x). You will get an answer. Input that answer back in function of g(x). If this answer matches the initial value of x, g(x) is inverse of f(x). 
(Remember this isn't a mathematical proof. It is an empirical proof.)
If you want to know how to mathematically prove it, let me know