Jillian is participating in a book-reading contest to raise funds for her local library. For every book Jillian reads, her mother pledged to make a donation.
A: The table shows how much Jillian's mother will donate. Find the pattern, and give the amount her mother will donate for 9 and 21 books read.
(Btw it won't let me upload a pic of the table so this is what it said)

BR: 3. 5. 7
MD: $15. $25. $35

(Ps. BR means books read and MD means money donated)

B: Write an equation showing the pattern from the table. Identify the variables.

C: Graph the equation.