This lesson is optional because it revisits content from an earlier course. If the preunit diagnostic assessment indicates that your students know this material, this lesson may be safely skipped.
In this lesson, students review completing the square and the quadratic formula as methods for solving quadratic equations. The lessons that follow require fluency with this skill.
Students make viable arguments and critique the reasoning of others as they decide whether different strategies for solving a quadratic equation are valid and decide whether the differentlooking solutions are equivalent (MP3).
Lesson overview
 16.1 Warmup: Find the Perfect Squares (5 minutes)

16.2 Optional Activity: Optional Ways to Solve It (15 minutes)
 Includes "Are you Ready for More?" extension problem
 16.3 Optional Activity: Optional Solve These Ones (10 minutes)
 Lesson Synthesis
 16.4 Cooldown: Oh, and Solve These Ones Too (5 minutes)
Learning goals:
 Explain (in writing) the reasoning used to solve a quadratic equation by completing the square and by using the quadratic formula.
 Justify whether two radical expressions are equivalent.
 Solve quadratic equations and explain the solution method.
Learning goals (student facing):
 Let’s solve quadratic equations.
Learning targets (student facing):
 I can solve quadratic equations by completing the square or by using the quadratic formula.
Standards:
 This lesson builds towards the standard: CCSS.HSAREI.B.4.bMS.AREI.4bMO.A1.REI.A.2c
IM Algebra 1, Geometry, Algebra 2 is copyright 2019 Illustrative Mathematics and licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
The Illustrative Mathematics name and logo are not subject to the Creative Commons license and may not be used without the prior and express written consent of Illustrative Mathematics.