Sal Khan, Monterey Institute for Technology and Education
Thinking about graphing on a coordinate plane, slope and other analytic geometry. Source: Khan Academy (www.khanacademy.org), used under the Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC-SA) license. All Khan Academy content is available for free at www.khanacademy.org. Khan Academy does not endorse the World Public Library.
Read this work at the World Public Library (library card needed).