Texas A&M University
Wtamu Virtual Math Lab: Intermediate Algebra: The Slope of a Line
This tutorial will show you how to find a the slope of graph, write a linear equation in slope-intercept form. You'll also learn how to determine whether two lines are parallel or perpendicular to each other. For advanced math students.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Standard Form in Linear Equations Useful
Dr. Math discusses the usefulness of standard form of linear equations on this page. The Dr. discusses parallel and perpendicular lines as well as graphing techniques. The Dr. touches on what the canonical form is and its usefulness.