KATE'S MATH LESSONS
  • Home
  • LESSONS
    • Pre-Algebra
    • Algebra 1
    • Geometry
    • Algebra 2
  • About
  • Contact
  • Blog
  • Shop
  • Courses
  • Home
  • LESSONS
    • Pre-Algebra
    • Algebra 1
    • Geometry
    • Algebra 2
  • About
  • Contact
  • Blog
  • Shop
  • Courses
Elimination Method (Level 1)                     Page 3 of 3

Example 2

Solve the system:  3x - 2y = 2   and   -3x + 5y = 13

Step 1: Add the equations vertically.
First, rewrite one equation right below the other.  Make sure the variables, equal signs, and constants are lined up.
Solve a system of equations using elimination.  katesmathlessons.com

After you get everything lined up, add straight down.
How to use the elimination method to solve a system of equations.

Did you notice what happened?  This time the x's canceled out.  The goal with the elimination method is to always get one of the variables to cancel, it doesn't matter which one.  0x is the same as 0, so we can rewrite the equation without it.

Step 2: Solve for the first variable.
Now that the x's are gone, you can solve the equation for y.
Solving a system using elimination.  katesmathlessons.com

Step 3: Solve for the second variable.

Now that you have one variable, we need to plug it in one of the original equations to find the other variable.  Pick the original equation that looks the easiest, you'll get the same answer no matter which one you choose.  We'll choose the first equation and plug in 5 for y.   

Pay careful attention to where you plug the value in!  Make sure you put the 5 in for the y-value.
How to use elimination to solve a system.  katesmathlessons.com

Step 4: Write answer as an ordered pair.
​Now that you know both x and y, put them together to write your answer as an ordered pair.  Make sure to write them in alphabetical order: x goes first, y goes second.
Writing answer to system of equations.

Step 5: Check your answer.
It's pretty easy to check your answer when using the elimination method.  We used the first equation to solve for x, so we need to check our answer in the second equation.  If you use the same equation twice, you won't catch a mistake if there is one.
How to check your answer to a system of equations.  katesmathlessons.com

​If we had plugged in x and y and it came out to a number other than 13, we would know to go back and look for a mistake along the way.

Elimination Method Video

Check out the short video below to see an example of solving a system of equations with the elimination method.


Practice

Ready to solve some systems on your own? Click the START button below to try a practice quiz on the elimination method.

Powered by Interact


Ready to try some harder elimination problems? 
Check out Level 2 Elimination Problems.
Picture
         1      2      3 
Want to try one of my digital math activities for free?  Click the link to grab the teacher version or student version.

Home

About

Privacy Policy

Lessons

Contact

Copyright © 2015 - 2021 Kate's Math Lessons