Overview
On this page, we discuss how to use the method of substitution to solve a system of two linear equations with two variables.
Basic Learning Objectives
These are the tasks you should be able to perform with reasonable fluency when you arrive at your next class meeting. Important new vocabulary words are indicated in italics.
- Solve a linear system of two equations with two variables by isolating a variable and substituting the result in the other equation.
Advanced Learning Objectives
In addition to mastering the basic objectives, here are the tasks you should be able to perform after class, with practice:
- Understand how to recognize when a linear system has no solutions or infinitely many solutions when solving by substitution, and what this means about the the graphs of the two linear equations.
To prepare for class
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Watch the following video (by Tyler Wallace) which shows how to solve a system of linear equations by isolating a variable:
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Watch the following video (by Khan Academy) which shows more examples of solving systems of linear equations by isolating a variable:
After class
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Watch the following video (by Tyler Wallace) which shows some special cases that can occur when solving by substitution:
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Watch the following video (by NancyPi) which shows many examples of solving a system of equation using substitution:
