Download Solving by Elimination Method Using the Multiplication Principle First

Math 52
7.3 "The Elimination Method"
Objective:
*
Solve a system of two equations in two variables using the elimination method.
Solving by Elimination Method
The elimination method for solving system of equations makes use of the addition principle. Some systems are much
easier to solve using this method.
Example 1: (Solving systems of equations by elimination)
Solve the following system of equations by using the elimination method.
x+y =5
2x + y = 4
a)
b)
2x y = 4
2x 5y = 12
Using the Multiplication Principle First
The elimination method allows us to eliminate a variable. We may need to multiply by certain numbers …rst, however,
so that terms become opposites.
Example 2: (Solving systems of equations by elimination)
Solve the following system of equations by using the elimination method.
5x + 3y = 17
4a + 7b = 11
a)
b)
5x 2y = 3
2a + 3b = 5
Page: 1
Notes by Bibiana Lopez
Introductory Algebra by Marvin L. Bittinger
c)
e)
2w + 1 3z = 0
3w = 24 4z
5x 2y = 3
15x + 6y =
9
7.3
d)
f)
2x + y = 15
4x + 2y = 23
1
1
x+ y =
3
2
1
6
1
2
7
x+ y =
2
5
10
Page: 2
Notes by Bibiana Lopez