1. 3.1 Graphing

2. The Rectangular Coordinate System
Quadrant I
Quadrant II
x-axis
origin
Quadrant III
Quadrant IV
y-axis

3. Each point in the coordinate system corresponds to an ordered pair (x,y)
Example: (3,5)
The first number is called x-coordinate and the second number is called y-coordinate
(3,5)

4. Plotting Points
When you plot the points, always look for the numbers on the x-axis (horizontal line) first: negative # is on the left, positive is on the right, then move up (if +) or move down (if -)
Ex: Plot (-2,3)
And (0, -4)
(-2, 3)
(0, -4)

5. More examples (1, 5) (-4, -4) (-1, 3) (6,0) (0, 2) (3/2,3) (4, -5)
(0, -3)

6. Graphing equations Steps Create a table with x and y
Give x at least 3 values if it is a linear equation, if not, give x at least 5 values
Find y
Form ordered pairs
Plot the ordered pairs
Connect the graph

7. Example 1 Graph y = 2x + 1 x y = 2x + 1 -2 Y = 2(-2) + 1 = -4 + 1 = -3
(-2, -3)
(0, 1 )
(2, 5 ) x
y = 2x + 1 -2
Y = 2(-2) + 1 = = -3
Y = 2 (0) = = 1 2
Y = 2(2) = = 5

8. Continue…
Y=2x +1
Order pairs
(-2,-3)
(0,1)
(2,5)

9. Y = (1/2)x + 2
For equation with fractions, what numbers should we choose for x?