System of Equations with 3 variables - Part 2

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Taught by YourMathGal
  • Currently 4.0/5 Stars.
7163 views | 1 rating
Part of video series
Meets NCTM Standards:
Lesson Summary:

In this lesson, Julie Harland shows how to solve a system of linear equations with three variables using the substitution method. She starts by solving for one variable in one of the equations, and then plugging it into the other equations to eliminate that variable. She then uses a combination of the addition and substitution methods to get two equations with two variables, which can be solved using either method. Finally, she plugs in those values to the original equations to check the solution. The lesson includes a detailed explanation of each step and is easy to follow along.

Lesson Description:

This video shows how to solve a system of 3 three linear equations in 3 variables using the substitution method, and also partly the addition (elimination) method to solve a system of 2 equations. The same problem is solved in the first part of this lesson series using the Addition Method.

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

Questions answered by this video:
  • How do you solve a system of 3 equations with 3 variables with the substitution method?
  • How do you solve the system of equations 3x + 2y + z = 1, x - 2y + 2z = 4, 2x + 4y + 3z = 9?
  • Where do you start when trying to solve a system of 3 equations in 3 variables?
  • How can you check your solution to a system of 3 equations?
  • Staff Review

    • Currently 4.0/5 Stars.
    This lesson does a great job of showing how to solve a system of 3 equations in 3 variables using the substitution method. This same problem was done in the previous lesson in this series using the elimination / addition method. The elimination method is actually used deep into this problem in 1 step because it is easier. Each step involved in this sometimes difficult process is shown. This is a great place to start to learn how to solve a system of 3 equations.