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Ch 7 Graphs and Linear Equations
Review on Graphing
Ordered Pair
y
8
6
(x, y)
4
2
-10
-5
“origin” (0,0)
5
-2
-4
-6
Coordinate Plane
-8
10
x
Ordered Pair
y
8
6
(5, 4)
4
2
-10
-5
“origin” (0,0)
5
-2
-4
-6
Coordinate Plane
-8
10
x
Ordered Pair
y
8
6
(5, -4)
4
2
-10
-5
“origin” (0,0)
5
-2
-4
-6
Coordinate Plane
-8
10
x
Ordered Pair
y
8
6
(-5, -4)
4
2
-10
-5
5
-2
-4
-6
Coordinate Plane
-8
10
x
Ordered Pair
y
8
6
(-5, 0)
4
2
-10
-5
(-5,0)
5
-2
-4
-6
Coordinates
-8
10
x
Graph (0, 6)
y
8
6
second
quadrant
-10
4
2
-5
third
quadrant
(0,6)first
quadrant
5
-2
-4
fourth
quadrant
Not in a quadrant
quadrants
if on either axis
-6
-8
10
x
What are the
coordinates?
Which quadrant?
y
8
6
4
2
(1,1)
-10
-5
5
-2
-4
-6
-8
10
x
y
8
6
4
(-3, 3)
-10
What are the
coordinates?
Which quadrant?
2
-5
5
-2
-4
-6
-8
10
x
y
8
6
4
What are the
coordinates?
Which quadrant?
2
-10
-5
5
-2
-4
-6
-8
(5, -2)
10
x
y
8
6
4
What are the
coordinates?
Which quadrant?
2
-10
-5
5
-2
(0, -5)
-4
-6
Not in a quadrant if on either axis
-8
10
x
7.2 Graphing Equations
Determine if the ordered pair is a
solution of the equation.
y = 2x + 1
(3 , 7 )
7 = 2(3) + 1
YES
The ordered pair (3,7) is a solution.
Determine if the ordered pair is a
solution of the equation.
4y - 3x = 22
(-2 , 4 )
4(4) – 3 (-2)= 22
16 + 6 = 22
YES
The ordered pair (-2,4) is a solution.
Determine if the ordered pair is a
solution of the equation.
y - 3x = -2
(-2 , 8 )
(8) – 3 (-2)= -2 ???
8 + 6  -2
NO
The ordered pair (-2,8) is not a solution.
Graphing Equations
• Make a Table
Making a Table
1. Solve the equation in y = format (slope
intercept form)
2. Pick your x values (-1, 0,1) unless slope is
a fraction and y-intercept is not
3. Plug in the x values into x in the equation
to find the corresponding y values
4. Plot the (x, y) ordered pairs on the
coordinate plane
Graph:
y=x
y
8
x
y
6
4
2
-10
-5
5
-2
-4
-6
-8
10
x
y
Find 3 solutions
8
6
y = 2x + 1
4
2
-10
-5
5
10
x
X Values
Y=2x + 1
Y Values (x,y)
1
2(1) +1
3
(1,3)
2(0) +1
1
(0,1)
-2
-4
-6
0
-8
-1
2(-1) +1
-1 (-1,-1)
Solve for ‘y’
9 x  3y  20
9x
9x
3y  9 x  20
3
3 3
20
y  3x 
3
Solve for ‘y’ means “get y all by itself”
y
Graph:
8
-2x + y = 5
y = 2x + 5
6
4
2
-10
-5
5
X
Y=2x +5
10
Y
(x,y)
x
-2
1 2(1) +5 7 (1,7)
0 2(0) +5 5 (0,5)
-4
-6
-1 2(-1)+5 3 (-1,3)
-8
Graph:
y
-2x + 3y = 15
8
3y = 2x + 15
2 x  15
y
3
-10
6
4
2
-5
Y=2/3x +5
x
Y=2/3x +5
5
10
y
x
(x,y)
-2
7 (3,7)
3
(2/3)(3) +5
0
(2/3) (0) +5
5
(0,5)
-3
(2/3)(-3)+5
3
(-3,3)
-4
-6
-8
Graph: 3x - y = 2
3x = y + 2
3x - 2 = y
y
8
x
y
6
4
2
-10
-5
5
-2
-4
-6
-8
10
x
•Assignment:
Page 311
(2-26 even, 28-31 all)
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