1. Objective- To use slope and y-intercept to
graph lines.
Graph the line which passes through (-2, 1) and has a
slope of -3. y
Steps
1) Plot the point.
2) Write slope as fraction
and count off other points. -3
m = -3 = 1 x -3 3
or m = -1 +1
3) Draw line through points.

2. -3 -4 Graph the line which passes through (3, 2) and has a slope of .y +4
Steps
1) Plot the point. +3
2) Write slope as fraction
and count off other points. 3
m = 4 x -3
or m = -4
3) Draw line through points.

3. -3 -3 -3 Graph the line which passes through (-5, 4) and has a
slope of -3 2 y
Steps
1) Plot the point. -3
2) Write slope as fraction
and count off other points. -3 +2
m = 2 x
3) Draw line through points.

4. -2 -5 Graph the line which passes through (-1, -3) and has a
slope of 2 5 y
Steps
1) Plot the point.
2) Write slope as fraction
and count off other points. 2
m = 5 +5 x -2
or m = -5 +2
3) Draw line through points.

5. -1 -1 -1 Graph the line with a y-intercept of 4 which has a slope of .2 y
Steps
1) Plot the point. -1
2) Write slope as fraction
and count off other points. +2 -1
m = 2 x
3) Draw line through points.

6. Any linear equation which is solved for y is in
Slope-Intercept Form of the Linear Equation
y = mx + b
Any linear equation which is solved for y is in
slope-intercept form.
Find the slope and y-intercept of the following linear equations:
4) y = x - 4 5 5
b = -4
1) y = 3x + 4
m = 8 8
m = 3
b = 4 -2 -2 -1
2) y = -2x - 1
5) y = x - 1
m =
b = 9 4 9 4
m = -2
b = -1
3) y = 5x
6) y = 6
m = 5
b = 0
m = 0
b = 6

7. Slope of Horizontal and Vertical Lines
Horizontal Lines
Vertical lines
x = -3
y = 2
Does not fit
y = mx + b
y = 0x + 2
m = 0
m = undefined y y
x = -3
y = 2 x x

8. Slope of Horizontal and Vertical Lines
Horizontal Lines
Vertical lines
(-2,2) (1,2)
(-3,2) (-3, -1) y y
x = -3
(-2,2)
(1,2)
y = 2
(-3,2) x x
(-3,-1)

9. -1 - 2 -3 - -3 -3 Slope of Horizontal and Vertical Lines y2- y1 y2- y1
Horizontal Lines
Vertical lines
(-2,2) (1,2)
(-3,2) (-3, -1) 1 2 1 2
y2- y1
y2- y1
m =
m =
x2- x1
x2- x1
2 - 2
-1 - 2
m =
m =
1 - -2 -3
m =
m = 3
Watch Out!
m = undefined
or there is “no slope”
m = 0
m = 0 for all
Horizontal Lines
m = undefined for
all Vertical Lines