Systems of EquationsSolving by Graphing
Systems of Equations
• One way to solve equations that involve two different variables is by graphing the lines of both equations on a coordinate plane.
• If the two lines cross the solution for both variables is the coordinate of the point where they intersect.
y = 2x + 0 & y = -1x + 3
Slope = 2/1y-intercept= 0
Up 2 and
right 1
y-intercept= +3
Slope = 1/-1
Up 1 and
left 1The solution is the point they cross at (1,2)
(1,2)
y = x - 3 & y = -3x + 1
Slope = 1/1y-intercept= -3
y-intercept= +1
Slope = 3/-1
The solution is the point they cross at (1,-2)
Graph y = x -3 y = x + 2
Solution= none
NUMBER OF SOLUTIONS OF A LINEAR SYSTEM
IDENTIFYING THE NUMBER OF SOLUTIONS
y
x
y
x
Lines intersectone solution
Lines are parallelno solution
y
x
Lines coincideinfinitely many solutions
Name the Solution
Name the Solution
Name the Solution
Systems of EquationsSolving by Graphing