Link to all pre-algebra videos http://phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=ade&wcsuffix=0775
Click on chapter 5, lesson 1
Link to all pre-algebra videos http://phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=ade&wcsuffix=0775
Click on chapter 5, lesson 1
Video 2.4, checking by substitution, http://www.phschool.com/atschool/academy123/english/academy123_content/wl-book-demo/ph-011s.html