# Homework Help: If (f o g)= 16x + 7 and g(x)= 2x - 1 , find f(x)

1. Jul 30, 2011

### Andolph23

1. The problem statement, all variables and given/known data

If (f o g)= 16x + 7 and g(x)= 2x - 1 , find f(x)

3. The attempt at a solution

I haven't done a problem like this in awhile so I dont remember exactly what to do. I think you plug g(x) into (f o g) to get 32x - 9 but I'm not sure if that's correct.
1. The problem statement, all variables and given/known data

2. Jul 30, 2011

### BloodyFrozen

If this is correct, you should try f(g(x)) and see if you get what it was originally

P.S. Notice your trying to get f(x)

3. Jul 30, 2011

### eumyang

Suppose that f(x) = Ax + B, a linear function. Given that, and that g(x) = 2x - 1, what is (f o g)(x)?
(Ignore for a moment that (f o g)(x) was already given.)

P.S. This should really be in the Precalculus subforum.

4. Jul 31, 2011

### SammyS

Staff Emeritus
What is (f○g○g-1)(x) ?

5. Aug 3, 2011

### BloodyFrozen

Wow, your good Didn't even think of that.