# Lesson 19

Quadratic Steps

These materials, when encountered before Algebra 1, Unit 7, Lesson 19 support success in that lesson.

### Lesson Narrative

The purpose of the lesson is to familiarize students with the processes for completing the square and steps for proving the quadratic formula. In the associated Algebra 1 lesson, students prove the quadratic formula by completing the square on the general standard form for a quadratic equation. The work of this lesson supports students by carefully examining steps that will be needed for the proof. Students construct viable arguments and critique the reasoning of others (MP3) as they identify and correct errors made in solving quadratic equations, and when they explain each step that should be taken to solve.

### Learning Goals

Teacher Facing

- Justify steps for solving an equation.

### Student Facing

- Let’s explore steps for solving an equation.

### CCSS Standards

Building Towards