Substitution (Jump to: Lecture | Video )

System of Equations
A System of Equations is a set of equations that has variables with the same values.

Below is a System of Equations:

3y = 2x - 2

4 - 4x = y

Substitution can be used to solve this set of equations.

Remember that "x" and "y" have the same values in each equation. The second equation tells us that "y" is equal to "4 - 4x". We can substitute this in for "y" in the first equation:

3(4 - 4x) = 2x - 2

Now, we just have to solve for "x". First, we apply the distributive property:

12 - 12x = 2x - 2

Next, we add 2 to each side.

14 = 14x

Now, we divide each side by 14 to solve for "x".

1 = x

Now that we know that "x" is equal to 1, we can plug it into either equation to solve for "y".

4 - 4(1) = y

0 = y

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