WILL MARK BRAINLIEST ! 12 POINTS !

Let b(t) be the number of unread books remaining on Alex's bookshelf after reading consistently for t months.

b ( t ) = 75 - 5t

So, b ( 9 ) = _____ .
Options : 70 or 30 or 45 or 15

This means that _____ ,
Options :
* After 9 days
* After reading 9 books per month
* After reading 9 books
* After 9 months

the _____ .
Options :
* Number of months that have passed is 70
* Number of unread books remaining is 30
* Number of unread books remaining is 45
* Number of months that have passed is 15