1. 2.1 Graphs of equations

2. The Rectangular Coordinate System
x-axis
origin
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) (0,0) (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 more values
Find y
Form ordered pairs
Plot the ordered pairs
Connect the graph

7. Example 1
Graph y = 2x + 1 x
y = 2x + 1 -1 1

8. Example 2
y = x2 – 4 x
y = x2 – 4 -2
y = (-2)2 – 4 = 4 – 4 = 0 -1 1 2

9. y = |x|
x y = |x|

10. Ex: y = 1/x
x y = 1/x