# Ch 10: Compass Math: Linear Equations

### About This Chapter

## ACT Compass Math: Linear Equations - Chapter Summary

As the day of the Compass Math test nears, you can prepare for questions that focus on the writing of linear equations. Your understanding of that topic and others will be stronger by completing the video lessons that are led by our professional instructors. Some more lessons you'll come across in the chapter look at the following:

- Definition of a linear equation and a system of equations
- How to use a system of equations
- Abstract algebraic equations
- Solving a system of linear equations in two variables
- Intercepts, standard form and graphing with linear equations
- Solving a linear system in three variables with no or infinite solutions
- Graphing zero and undefined slope

Study the several effective examples in the lesson transcripts as well as in the videos as you go through the chapter. If you want to double-check something after watching a video, you can easily do that with the video tags.

### Objectives of the ACT Compass Math: Linear Equations Chapter

ACT Compass tests are used by colleges to make certain that students are placed in courses at the appropriate levels. The math test assesses your strengths in five content domains, and this chapter's topic falls under the algebra domain. You should expect to see questions that ask about solving linear systems with one or multiple variables. You'll be answering multiple-choice questions on the exam, and the practice questions you can use in this chapter for quick self-assessment have the same format. The test is computer-based and, just as in the case of the chapter's quizzes, you'll be able to see your results after you're done.

### 1. What is a Linear Equation?

Most cars won't be able to run for more than 250,000 miles, so how much longer will your car live? Linear Equations are the most basic kind of algebraic function and can help you answer questions exactly like this. Learn about what they look like, how they come up in your life and why they are powerful tools.

### 2. Linear Equations: Intercepts, Standard Form and Graphing

Do you know what to do if an equation doesn't look like y=mx+b?! If not, then this video is for you. Chances are the equation is in standard form, so we'll learn how to use standard form equations, how to graph them and why they can be helpful.

### 3. Abstract Algebraic Examples and Going from a Graph to a Rule

Just because you now know what a linear equation is doesn't mean that you are a master! This video will help you learn how to apply your knowledge of linear equations in more abstract algebraic ways.

### 4. Graphing Undefined Slope, Zero Slope and More

There are two special cases when it comes to slopes on the xy plane: horizontal and vertical lines. Without any more information, these examples can be pretty confusing. But with a little instruction, they end up being some of the easiest lines to graph!

### 5. How to Write a Linear Equation

Simply knowing how to take a linear equation and graph it is only half of the battle. You should also be able to come up with the equation if you're given the right information.

### 6. 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.

### 7. 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.

### 8. 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.

### 9. 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.

### 10. 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.

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### Other Chapters

Other chapters within the ACT Compass Math Test: Practice & Study Guide course

- Compass Math: Integers
- Compass Math: Decimals
- Compass Math: Fractions
- Compass Math: Exponents
- Compass Math: Roots & Radicals
- Compass Math: Percents
- Compass Math: Ratios, Rates & Proportions
- Compass Math: Median, Mean & Mode
- Compass Math: Algebraic Equations & Expressions
- Compass Math: Substituting Values
- Compass Math: Monomials & Polynomials
- Compass Math: Factoring Polynomials
- Compass Math: Matrices & Absolute Value
- Compass Math: Inequalities
- Compass Math: Complex Numbers
- Compass Math: Logarithms
- Compass Math: Basic Geometry
- Compass Math: Lines & Angles
- Compass Math: Polygons
- Compass Math: Triangles
- Compass Math: Quadrilaterals
- Compass Math: Circles
- Compass Math: Similar Figures
- Compass Math: Complex Figures
- Compass Math: Constructions
- Compass Math: Area, Circumference & Perimeter
- Compass Math: Mathematical Modeling
- Compass Math: Quadratics
- Compass Math: Quadratic Functions
- Compass Math: Trigonometric Functions
- Compass Math: Rational Functions
- Compass Math: Function Operations
- Compass Math: Trigonometric Identities
- Compass Math: Trigonometric Equations
- Compass Math: Trigonometric Applications
- Compass Math: Trigonometric Graphs
- Compass Math: Graph Symmetry
- Compass Math: Polar Coordinates & Parameterization