They're just learning to graph linear equations. I've begun to realize how hard it is for many people to see a point as being the equivalent of two pieces of information (the x-coordinate and the y-coordinate). One visual object turns into two numbers. So of course they struggle with graphing lines. The matching problem from the book gave 4 equations, all y = 5x+b, with 4 different numbers for b, along with their graphs. They liked doing that.
Today I'm going to start by asking them to graph 2x+3y = 6. That will take a while. Then I'm going to hand out the sheet I just made with all 8 possible equations like this (± 3y, ±6, and swapping the 2 and 3) and all 8 graphs, so they can do another matching problem. That will
[How do I show a Google doc file here?]