Math 10
Unit: SYSTEMS of Equations
Chapter 2 Notes
Solving Systems of Equations by Addition/Subtraction
Name: _________________
We can solve a system of equation without using a graph using algebra. Solving involves finding the x and y
that satisfy both equations. Right now you know how to solve equations in one variable (x). Now we will learn
how to solve systems with two variables (x and y). Since we already know how to solve a one variable system,
we will just learn to transform our two variables system into one variable and then solve that. we do this using
the method of addition or subtraction to eliminate one of the variables – then solve the one variable system
Ex. 1: Find the solution of the following systems of equations (by addition/subtraction):
1.
4x - 3y = 20
2.
4x + 3y = 3
3.
2x – 3y + 18 = 0
6x - 3y = 24
3x - 2y = -19
5x + 2y + 7 = 0
1
Math 10
Unit: SYSTEMS of Equations
Chapter 2 Practice
2
WORKSHEET:
1. Find the solution of the following systems of equations (by addition/subtraction):
a) 2x – 3y + 9 = 0
b) 4x – 3y – 6 = 0
c) 2x – 5y + 5 = 0
x + 3y + 9 = 0
3x – y + 3 = 0
3x + 5y + 20 = 0
2. Find the solution of the following systems of equations (by add/subtract) – watch out for # of solutions!!
a)
2x – 4y + 8 = 0
b)
x – 2y + 4 = 0
c)
2x + 4y – 8 = 0
d) 2x + 4y – 8 = 0
x + 2y + 4 = 0
2x – 4y + 8 = 0
x + 2y + 4 = 0
x + 2y - 4 = 0