1. Equations and Inequalities in 2 Variables; Functions
Chapter 3
Equations and Inequalities in 2 Variables; Functions

2. Section 3.2
The Slope of a Line

3. Classifying lines by their slopes
If the slope is positive, the line inclines upward from left to right.
If the slope is negative, the line declines downward from left to right.
If the slope is zero, the line is horizontal.
If the slope is undefined, the line is vertical.

4. Finding the slope given a graph
Slope = m = Rise
Run
Find 2 points on the line.
Count the vertical distance. (RISE)
Count the horizontal distance. (RUN)
Set up the fraction and simplify.
Note if the line inclines upward or downward to determine the sign.

5. Finding slope from 2 ordered pairs
Slope = m = y2 – y1
x2 – x1
EX: find the slope of the line through the given points
(1, 7) and (3, 1)
(-7, 9) and (2, 3)

6. Graphing using slope Slope – Intercept form: y = mx + b
Slope is m and the y-intercept is (0, b)
1. Identify the values of m and b.
2. Plot (0, b) on the y-axis.
3. Use m = rise to plot a 2nd and 3rd point.
run
4. Connect with a straight line.

7. Ex: graph
1. y = ½ x – 3
2. y = -3x – ¼
3. 3x – 2y = 9