Lesson plan

Understand why radical equations can have extraneous solutions by examining graphs

teaches Common Core State Standards CCSS.Math.Content.HSA-REI.A.2 http://corestandards.org/Math/Content/HSA/REI/A/2
teaches Common Core State Standards CCSS.Math.Content.HSA-REI.D.11 http://corestandards.org/Math/Content/HSA/REI/D/11

You have saved this lesson plan!

Here's where you can access your saved items.

Content placeholder

or to view additional materials

You'll gain access to interventions, extensions, task implementation guides, and more for this lesson plan.

Big Ideas: Solutions for radical equations can be found analytically and/or using tables and graphs, and the inverse relationship between square root and quadratic functions can be used to explain the notion of extraneous roots. In this lesson, students will solve a square root equation analytically and by graphing. While solving analytically, an equivalent quadratic equation is produced; graphing this quadratic equation reveals that although the quadratic equation is equivalent to the square root equation, it contains a solution which is an extraneous solution of the original quadratic equation. Special Materials: graph paper