This lesson is optional because it revisits material from earlier grades.

In this lesson, students recall what they learned about solutions to equations in one variable and in two variables. They also continue to practice modeling relationships with equations and to make sense of equations and their solutions in context (MP2, MP4).

Students verify and find solutions to given equations by checking if the values satisfy the equations and by reasoning. Some students may choose to solve equations algebraically or by performing certain sequences of steps they learned in middle school, but students are not expected to rely on algebraic methods to answer questions here.