McDougal LittellAlgebra 1© 2007*All videos are based on problems from this textbook. 2.7 Simplifying Expressions4.6 Identifying Direct Variation & Writing Direct Variation Equations4.4 Counting and Calculating Slope5.1/5.2 Rewriting in Slope-Intercept Form (SIF)5.1/5.2 Word Problems (SIF & PSF)5.4 Rewriting in Standard Form5.4 Equations of Special Cases5.5 Equations for Parallel & Perpendicular Lines5.6/5.7 Scatter Plots & Line of Best Fit