Earlier in the course, students have spent some time writing equations in one variable, two variables, and multiple variables to represent relationships and constraints. They have also rearranged equations to isolate a particular variable. This Warm-up activates that prior knowledge, preparing students to write equations for linear functions that involve two or more operations, and then to write their inverses.

To ensure access, the equations students are expected to write are scaffolded—starting with one operation and moving to two operations, from using numbers and letters to using only letters. The scaffolding also allows students to see structure in the equations, which would be helpful when they try to reverse the process.