4 books
1) We notice that x stands for months and y, the number of comic books.
2) Since the number of Jacks' books is given by y= 2x +15, let's plug into that the number of months x=2
y=2x +15
y= 2(2) +15
y= 4 +15
y=19 books
Looking at the graph we can locate the number of books, Kane is going to have after 2 months: ( 2,15) So Kane will have 15 books in 2 months' time.
3) So Jack is going to have 4 books more than Kane.
4 books