I have no idea what i am doing, please help. Please explain your answer too please.

Answer:
A.
Step-by-step explanation:
If you plug g(x) into f(x), you should get 2x - 9
What this question is asking is for you to replace the x in f(x) with the whole equation of g(x) (or vice versa because of the answer choices). Once you plug in one equation into the other, you should find your outcome and your answer.