Answer:
B
Explanation:
The steps in the original function of f of B are
1. multiply by 2
2. subtract 9
Then the steps of the inverse equation would be
1. add 9
2. divide by 2
And this is what we see here. G is actually the inverse of f. Therefore B is the correct answer. If you repeat the same process for the other answers you'll find that it doesn't actually make an inverse.
You can also graph these to see whether or not its an inverse.