This lesson is optional because it revisits material from earlier grades. In this lesson, students revisit the idea that graphs can be a useful way to represent relationships. Students are reminded that each point on a graph is a solution to an equation that the graph represents. They analyze points on and off a graph and interpret them in context. In explaining correspondences between equations, verbal descriptions, and graphs, students hone their skill at making sense of problems (MP1).

In this lesson, students are also introduced to the use of graphing technology to graph equations.