1. Slope basically describes the steepness of a line
Slope of a Line
Slope basically describes the steepness of a line

2. If a line goes up from left to right, then the slope has to be positive
Conversely, if a line goes down from left to right, then the slope has to be negative

3. Definitions of Slope
Slope is simply the change in the vertical distance over the change in the horizontal distance

4. The formula above is the one which we will use to find the slope of specific lines
In order to use that formula we need to know, or be able to find 2 points on the line

5. Find the slope of the line y = -2x + 1
Find two points on the line.
If x = 0, then y = ?
If x = 1, then y = ?
Using the two points (0, 1) & (1, -1), insert into the slope formula

6. Examples

7. Examples

8. Using Coordinates
If given two points on a line, insert into the formula directly.

9. Examples

10. Examples

11. Examples

12. A slope of means the line goes up 1, and to the right 3

13. Examples
(-4, 3) (-10, 9)
m = -1
(4, 2) (-5, -4)
m = 2/3

14. Horizontal lines have a slope of zero while vertical lines have no slope (undefined)
m = 0
Vertical
Horizontal
m = no slope

15. Examples
(-3, 2) (1, 2)
m = 0/-4= 0
Since the slope is 0, this is a horizontal line
(-4, 3) (-4, -2)
m = -5/0
Since you cannot divide by 0, this line has an “undefined” slope

16. Assignment
8.3A: 1 – 10, 21 – 30, 40