Lesson objective: Fluently identify whether equations are linear or nonlinear.

This lesson helps to build fluency with graphing and identifying nonlinear functions. Graphs are used here, because they support visual identification of linear versus nonlinear functions. This work develops students' understanding that not all functions are linear.

Students engage in Mathematical Practice MP.5 (use appropriate tools) as they can choose whether to create a table of values or a graph in order to tell whether a function is linear or nonlinear.

**Key vocabulary:**

- function
- linear
- nonlinear

**Special materials needed:**