For this case we have the following functions:

We must find
By definition of operations with functions we have:

So:

Answer:
Option A

7a)

If n is the amount of sides then there's 38 sides in a polygon with 665 diagonals
7b)
We do the same as 7a) but with 406. We get that
and
. A polygon cant have 30.04 sides
Answer:
74 and 740
Step-by-step explanation:
Answer is D unless theres a nother right answer