Lesson objective: Write systems from a description, and determine the best way to solve based on their structure.

This lesson helps to build procedural skill with solving by substitution or by other algebraic methods. Verbal descriptions and equations are used here because they support students in choosing the most efficient algebraic method. This work develops students' understanding that we can write and solve systems of equations algebraically, even when substitution is not the most efficient method.

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they write systems and decide whether substitution or another algebraic method is the best way to solve the system.

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