Let f(x) = 8x + 4 and g(x) = 3x − 9. Find the function and its domain.

Question

I am not sure what x should be. I have the (-infinity, infinity) but I am not sure how to get the function.

Answer 1

Find the function?  You already have two functions!

For each function, the domains are all Reals and the ranges are also all Reals.

 

Perhaps you omitted some other part of this question?