Put into slope intercept form
2x – y = -9
-4y = -3x – 2
x + 3y = 2
x+y=4
Graph
5x – 10y = 20
Put in slope
intercept form:
-10y = -5x + 20
Y=½x+2
Solving Linear
Systems by Graphing
Definition
• A solution of a system of linear
equations in two variables is an ordered
pair (x,y) that satisfies each equation in
the system.
• Example: The solution of these two
linear equations, y = -2x + 4 and y = x – 2
is (2, 0)
How do we find the solution?
• You can find the solution of two linear
equations by graphing each of them on the
same graph and locating the point in which
they intersect.
• After finding the point of intersection, you
can check your work by plugging the
ordered pair into each equation.
Lets Try It!
Equation 1: x + 2y = 5
Equation 2: 2x – 3y = 3
STEP 1: Put equations into slope intercept form.
Equation 1:
Equation 2:
STEP 2: Graph each line.
STEP 3: See where the lines intersect
Intersection:
(3, 1)
STEP 4: Check your work
• Plug the ordered pair into both equations.
Answer: (3,1)
Equations: x + y = -2
2x – 3y = -9
Step 1: y = -x - 2
You Try
Step 3: (-3,1)
Step 4:
Step 2:
Answer: (-3,1)
Homework: pg. 401-402 # 17-22