2x + y =7
2x - 2y = -8
( 1, 5)
6x + 4y = 0
6x + y = 9
(2, -3)
Use when one equation is already
solved for a variable or can be easily
rearranged.
Substitution Method
4y + 2x = 5
x = 8 - 2y
No solutions. The system is inconsistent.
5y - 3x=6
( 1/2, 3/2)
10x + 7y = 49
10y - x = 70
(0, 7)
Use when the equations are lined up in
standard form (Ax + By = C) and adding
or subtracting eliminates a variable.
Elimination Method
2x + y = 8
y - x = 2
(4,2)
x + y = 20
3x + 11y = 100
(15,5)
164c + 24d = 4240
d = 2c
(20, 40)
3w + 3f = 17.70
2w + 3f = 15.55
(3.75, 2.15)
Systems of equations have how many solutions?
One
None
Infinity
2x + y = 3
x + 3y =12
( 3, -3)
x + 3y = 3
-x + y = -3
(3, 0)
6x + 3y = 9
-2x + y = -3
Infinite Solutions
5u +7v = -25
11u + 6v = -8
(2, -5)
A rectangular array of numbers.
Matrix
12w + 10n = -14
4w + 3n = -11
(1, -2)
2x + y = 1
5x + 10y = -10
(0, 1)
u + 2v = 3
4u + 8v = 12
Infinite Solutions
x + y = 1
x + 3y = 9
(-3, 4)
A matrix that includes the coefficients and constants from a system of equations.
Augmented Matrix
5a -2b = 3
2a - b = 0
(3, 6)
x + 2y = 8
x - 2y = 4
(6, 1)