> I don't think it is the case that I learned this method > once long ago and subsequently forgot it, so I am surprised > I never saw it before. How well known is this method? Is it > taught much? I don't find it in my favorite College Algebra > text (by C.H. Lehmann), and it doesn't show up in the first > three pages from Googl(R)ing "polynomial factor." At least > one of my more advanced clients had never seen it before either.
I first encountered this just 3 years ago, where the method was used in the intermediate algebra classes at a university I was teaching at back then. Like you, I was amazed that I had never heard of this before, especially given the amount of exposure to algebra and precalculus mathematics I've had over the past 35 years (my own studies, tutoring, TA classes, classes taught, articles in teaching journals, etc.). I wrote the following about it in a 28 April 2006 post at
> This method, sometimes called "factoring by grouping" > is mentioned in current texts:
Factoring by grouping usually denotes a more general method than what you described, although factoring by grouping is certainly used in the method you described. I've often seen the method you described called the "AC Method". The AC Method is great for students weak on creativity and "seeing things", but who are good at following specific easy to describe cut-and-dried procedures. There seems to be a lot about it on the internet: