The answer is 23.
Good luck :)
Not sure about remainder theorem but I'm sure that the last terms should all multiply tho the last term
see the expanded form is -45
so the last terms of each binomial should multiply to -45
3 times -5 times ?=-45
-15 times ?=-45
divide by -15
?=3
the question mark is 3
<u>ANSWER</u>

<u>EXPLANATION</u>
Given 
and

We want to find

This means we substitute the function
in to another function
and evaluate.
This implies that;

We expand the parenthesis to obtain;

We simplify further to obtain;

Hence the correct answer is A
To get the inverse, first off do a quick switch on the variables, and then solve for "y".