Answer:
A: The origin is the bottom-left corner of the graph, representing 0 months, 0 books. The x-axis represents months, with a scale of 1 month per line. The y-axis represents the amount of comic books, with a scale of 4 books per line.
B: The slope of Sara is 2, since she collects 2 books per month ([tex]\frac{20-12}{4}=2[/tex]), whereas Ashton collects 3 books per month, resulting in a slope of 3.
The y-intercept of Sara is 12, since that is the amount of comic books she started with. Ashton started with 2 comic books, so his y-intercept is 2.