Answer:
The annual total cost is $135 when he purchases 17 books
Step-by-step explanation:
Given function is:
C(b) = 5b + 50
Here c is the output which is cost and b is the input which is number of books purchased in an year.
In order to find the total cost when he purchases 17 books, we have to put 17 in place of b and find the cost.
So,
Putting b = 17
[tex]C(17) = 5(17) + 50\\= 85+50 = 135[/tex]
Hence,
The annual total cost is $135 when he purchases 17 books