# Ch 7: McDougal Littell Algebra 1 Chapter 7: Systems of Linear Equations & Inequalities

### About This Chapter

## How It Works:

- Identify the lessons in the McDougal Littell Systems of Linear Equations & Inequalities chapter with which you need help.
- Find the corresponding video lessons with this companion course chapter.
- Watch fun videos that cover the systems of linear equations and inequalities topics you need to learn or review.
- Complete the quizzes to test your understanding.
- If you need additional help, rewatch the videos until you've mastered the material or submit a question for one of our instructors.

## Students will learn to:

- Define a system of equations
- Use a system of equations
- Solve a system of equations in two variables
- Solve a system of equations with two unknowns
- Figure out system of equations practice problems
- Solve different types of linear systems in three variables
- Graph inequalities

*McDougal Littell is a registered trademark of Houghton Mifflin Harcourt, which is not affiliated with Study.com.*

### 1. What is a System of Equations?

So what happens if we want to compare more than one equation? Welcome to a 'system' of equations! Learn what one is, how to solve them and when they come up in real life.

### 2. How Do I Use a System of Equations?

There are a few classic algebra word problems, such as the one about two trains traveling at different speeds. In this lesson, you'll learn how to take a word problem and convert it into the system of equations that will allow you to find the answer using either substitution or elimination.

### 3. How to Solve a System of Linear Equations in Two Variables

Watch this video lesson to learn how you can solve a system of linear equations in two variables by using the substitution method. Learn how easy it is to use on any linear system in two variables.

### 4. Solving a System of Equations with Two Unknowns

When you have two variables and two equations, is solving the problem four times as hard? No! Not when you use the substitution or elimination method to solve systems of equations. We'll practice both in this lesson.

### 5. Solving Problems Involving Systems of Equations

Did you ever encounter a problem where you seem to have lots of information, but still have a couple of critical numbers missing? In this lesson, we'll practice solving word problems that require us to set up systems of equations.

### 6. How to Solve a Linear System in Three Variables With a Solution

After watching this video lesson, you will be able to solve a linear system in three variables using the elimination method. Learn the simple operations that are needed to solve your system.

### 7. How to Solve a Linear System in Three Variables With No or Infinite Solutions

In this video lesson, you will learn to recognize when a linear system has no solution or an infinite number of solutions. You will also learn how to go about solving each of these types of systems.

### 8. Graphing Inequalities: Practice Problems

If you're already pretty familiar with what inequalities are and just looking for a place to practice your skills, this is the place. This lesson covers topics like 1-variable, 2-variable, compound, and systems of inequalities.

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### Other Chapters

Other chapters within the McDougal Littell Algebra 1: Online Textbook Help course

- McDougal Littell Algebra 1 Chapter 1: Expressions, Equations & Functions
- McDougal Littell Algebra 1 Chapter 2: Properties of Real Numbers
- McDougal Littell Algebra 1 Chapter 3: Solving Linear Equations
- McDougal Littell Algebra 1 Chapter 4: Graphing Linear Equations & Functions
- McDougal Littell Algebra 1 Chapter 5: Writing Linear Equations
- McDougal Littell Algebra 1 Chapter 6: Solving & Graphing Linear Inequalities
- McDougal Littell Algebra 1 Chapter 8: Exponents & Exponential Functions
- McDougal Littell Algebra 1 Chapter 9: Polynomials & Factoring
- McDougal Littell Algebra 1 Chapter 10: Quadratic Equations & Functions
- McDougal Littell Algebra 1 Chapter 11: Radicals & Geometry Connections
- McDougal Littell Algebra 1 Chapter 12: Rational Equations & Functions
- McDougal Littell Algebra 1 Chapter 13: Probability & Data Analysis