There is an error, which is corrected, around the 7 1/2 minute mark where the slope should be positive 3/4.
Covers the algebraic formula used to find the slope of a line passing through two points. More examples are in the next video, Graphing 12. This is part 11 of a series of videos about graphing lines.
More free YouTube videos by Julie Harland are organized at http://yourmathgal.com