Solving Systems by Substitution
Subject:
Algebra [1]
A good way to solve systems of equations is by substitution. In this method, you solve on equation for one variable, then you substitute that solution in the other equation, and solve. Example:
1. Problem: Solve the following system:
x + y = 11
3x - y = 5
Solution: Solve the first equation for y
(you could solve for x - it
doesn't matter).
y = 11 - x
Now, substitute 11 - x for y
in the second equation. This gives
the equation one variable, which
earlier algebra work has taught
you how to do.
3x - (11 - x) = 5
3x - 11 + x = 5
4x = 16
x = 4