Please, post just one problem at a time, or (if you post more than one), indicate which one you want to focus on first. Even more important, please do whatever you can to get started on each problem; I'm sure you know at least some basics.
What does "intersecting" mean? Look it up if you're not sure.
Then what would "two intersecting lines" look like? Draw the graph, or at least explain in words what the graph would look like.
