Video: http://www.virtualnerd.com/algebra-1/polynomials-and-factoring/trinomial-factorization/leading-coefficient-not-1/factor-by-a-c-method
Simplified X Method Video: https://www.youtube.com/watch?v=-RYPaC_hBUU
Video: https://www.youtube.com/watch?v=0C74NekAh1c
Notes: http://www.regentsprep.org/regents/math/algtrig/atv1/LgroupingBox.htm
More: http://www.regentsprep.org/regents/math/algtrig/atv1/Ltri3.htm
Practice with 2 examples: http://www.regentsprep.org/regents/math/algtrig/atv1/revfactorgrouping.htm
10 Items Quiz: https://www.thatquiz.org/tq/practicetest?mz43m4iyh630