factoring: https://www.youtube.com/watch?v=1tL8CYi_mE8&feature=youtu.be
factoring bottoms up and grouping: https://www.youtube.com/watch?v=FeBYZ_N-QTI&feature=youtu.be
solving by factoring: https://www.youtube.com/watch?v=N6eFrMdIb0k&feature=youtu.be
solving polynomial equations by factoring: https://www.youtube.com/watch?v=Dj_51JSMdZk
solving polynomial equations by factoring: https://www.youtube.com/watch?v=azv8uRW7-ho&feature=youtu.be