# Lesson 16

### Lesson Narrative

This lesson is optional because it revisits content from an earlier course. If the pre-unit 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 different-looking solutions are equivalent (MP3).

### Learning Goals

Teacher Facing

• 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.

### Student Facing

• I can solve quadratic equations by completing the square or by using the quadratic formula.