1. Ch 4.2 & 4.3 Slope-Intercept Method
Objective:
To identify the slope and y-intercept and graph using the Slope-Intercept Method.

2. 3 Methods of Graphing
Table (T-Chart)
Intercepts
Slope-Intercept x y

3. where the line crosses y-axis
Definitions
Slope-Intercept Form: y = mx + b
Slope (m):
rise/run
as a fraction
y-Intercept (b):
where the line crosses y-axis

4. Draw a line through the two points
Rules
1) Use the y-intercept (b) to plot the first point
(0, b)
1) Use slope (m) to “count” rise/run from the y-intercept to plot the second point
rise/run from (0, b)
Draw a line through the two points

5. Identify the slope (rise/run) as a fraction and the y-intercept.
1) y = x - 4 5 -2
2) y = x - 1 8 9 4 -1 5 -2
-4 = b
m =
m =
= b 8 9 4
4) y = -2x - 1
3) y = 3x + 4 3 -2
-1 = b
m =
4 = b
m = 1 1
5) y = 5x
+ 0
6) y =
0x + 6 5
m =
0 = b
m =
6 = b 1 1

6. Example 1 y +3 +2 +3 +2 x Plot the y-intercept rise +2 (up)
run +3 (right) +3 +2 +3 +2 x

7. Example 2 -1 or y -2 +1 +2 x rise -1 (down) run +2 (right)
rise +1 (up) x
run -2 (left)

8. Example 3
y = 2x + 3 y +1
rise +2 (up) +2
run +1 (right) x

9. Example 4 -3 or y -2 x +3 +2 rise -3 (down) run +2 (right)
rise +3 (up) x
run -2 (left) +3 -3 +2

10. Classwork
Graph each equation 1) 2)

11. 3) 4)

12. 5) 6)