http://www.ck12.org Chapter 3. Parallel and Perpendicular Lines
Use the slope formula to determine the slope. Use (2, 2) as(x 1 ,y 1 )and (4, 6) as(x 2 ,y 2 ).
m=6 − 2
4 − 2
=
4
2
= 2
Therefore, the slope of this line is 2. This slope is positive.
Example B
Find the slope between (-8, 3) and (2, -2).
m= 2 −−^2 (−−^38 )=− 105 =−^12
This is a negative slope.
Example C
Find the slope between (-5, -1) and (3, -1).