The Substitution Method involves solving one of the equations for one of its variables.

The Substitution Method involves solving one of the equations for one of its
variables. You solve for the first variable and place that value in the second
equation to solve for the second variable. So, now that Lisa has explained this
to you, you should be able to solve this set of equations:

x+2y=2
3x+4y=-4

First, Lisa tells you to solve the first equation for "x". She says you should get
x=-2y+2.

Second, Lisa explains that you should substitute the expression for "x" which is
-2y+2 to solve for the "y". Your new problem should look like this:

3(-2y+2)+4y=-4

This should equal y=5.

Third, she says to substitute that value for "y" into the revised first equation. I
t should look like this:

x=-2(5)+2

Lisa says that the x=-8. So your final answer is (-8,5). Lisa has done well at solving
this substitution problem. Lisa says that this is one of the easiest ways to Solve a
system of Linear Equations. Lisa says thanks for coming by and visiting and she hopes
that you understand the substition better.

Now try some on your own:

1. x+5y=10 and 3x+6y=12

2. x-15y=20 and 4x+3y=28 (This is a hard one if you get it you know how to do it!!

The answers to the two problems:

1.(20,2)

2.(7.62,-.83)