You do realize that this is a help site, not an answer site. To help you so that you can answer questions on your own during your test, we must see what you are doing on your practice problems. Please show your work in the future.
One way to solve these inverse problems is: (1) state f(x) = y, (2) solve for x in terms of y, (3) switch x and y, and (4) replace y with g(x), you are done.
So y = what?
So x = what?
What do you get when you switch x and y?
I'll get you started.
$f(x) = log_4(x + 5) - 3.$
$y = log_4(x + 5) - 3 \implies y + 3 = log_4(x + 5) \implies x + 5 = 4^{y - 3} \implies what?$