The mathematical purpose of this lesson is to work with equivalent equations that are multiples of one another. In the first activity after the Warm-up, students examine the effect on the graphs of the equation of multiplying an equation by a constant. In the second activity, students find a value that can multiply an equation to achieve a target coefficient for a given variable. In the associated Algebra 1 lesson, students use the skill of multiplying an equation by a constant when solving systems of equations by elimination.

Students attend to precision (MP6) when they use precise language to describe a reason why systems of equations go together. Students look for and make use of structure (MP7) when they recognize two equations to be equivalent.