SLE - Solve Systems of Equations Using Elimination (Lesson)

Solve Systems of Equations Using Elimination

The final way we will learn how to solve systems of equations is by elimination. When we use elimination, we want to create a system of equations in which one variable has coefficients that are opposites. Opposites are two numbers that have the same value, but opposite signs. When you use elimination you ADD the two equations together:

2x + y = 9

3x - y = 16

Add the two equations together.

2x + y = 9

+3x - y = 16

5x = 25

x = 5

So now that we know that x = 5, we can substitute that back in to either equation to find y.

2(5) + y = 9

10 + y = 9

y = -1

So, the solution to this system of equations is (5, -1)!

Watch this video to try a few more examples - there are some tricky ones!

Solving Systems of Equations Using Elimination Practice

Solve these systems of equations using elimination.

1. 16x - 10y = 10 and -8x - 6y = 6
2. x + 2y = 3 and -3x - 6y = 1
3. -3x + y = 6 and 9x - 3y = -18
4. -x - 7y = 14 and -4x - 14y = 28

TO VIEW THE SOLUTIONS ONCE YOU HAVE PRACTICED, CLICK HERE. Links to an external site.

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