# Solve Systems of Equations by Graphing

#### 1 Hook

Present scenario of which cell phone plan would be the best.

Choose which of the following cell-phone plans would be best. Why?

#### 2 Direct Instruction

Watch and take notes on the lesson video.

http://youtu.be/-N5m7ZZCzgc?list=PL6O7l68qwx2D8kvtSqNJWE1g9QEqEhaI8

#### 3 Guided-Collaborative Practice

In a small group, or dyad, work on Activity 1: "Exploring Solutions to Linear Systems Graphically." from *Cooperative Learning and Algebra 1* by Becky Bride. (pages 293-295)

Students wil ask and answer the questions with the group. Come to consensus on a solution.

Ask and answer the questions with the group. Come to consensus on each inquiry.

#### 4 Formative Assessment

Students answer two questions:

What is the solution to the system?

- Students are given a system which they will graph and then answer the quick-question with the ordered pair.

Is the given ordered pair a solution to the system?

- Students are given an ordered pair and a system to determine if the solution is appropriate.

- What is the solution to the system? Give your answer as an ordered pair.
- Is the given ordered pair a solution to the system?

#### 5 Independent Practice

Students complete pages 296 and 297 (or a selection of the 8 questions) to determine if they have a solid understanding of graphing systems and determining if an ordered pair is a solution of a given system.

For #1-4 on the first side, determine the solution of each system by graphing. Give your answer as an ordered pair.

For #1-4 on the second side, determine if the ordered pair is a solution of the given system.

#### 6 Wrap-Up

Students will take a moment to identify the three types of systems they have explored graphically: parallel- inconsistent; intersecting - consistent/independent; concurrent-consistent/dependent.

Students will also give a written description of how to solve solutions graphically and how to determine if an ordered pair is the solution to a given system.

Draw the three types of systems and identify each.

Explain how to solve a system graphically

Explain how to determine if an ordered pair is the solution to a given system.