Unit 4, Lesson 7
Explaining Steps for Rewriting Equations
Integrated Math 1
Preparation
Lesson Narrative
This lesson serves two main goals. The first goal is to further develop the idea of equivalent equations. Students think about and articulate how they know that the equations produced using acceptable moves are indeed equivalent. The process is an opportunity to practice constructing logical arguments and critiquing the reasoning of others (MP3).
The second goal is to refamiliarize students with equations with no solutions (which they encountered in grade 8), and with a move that might appear acceptable (dividing each side of an equation by the same variable expression) but would in fact lead to the wrong conclusion.
- Explain (orally and in writing) why performing certain operations on an equation may create equivalent equations but performing other operations may not.
- Understand that dividing by a variable is not used in solving equations because it can lead to equations that have fewer solutions than the original equation.
- Understand that equations that are not true for any value of the variable(s) do not have solutions.