What's your favorite method for factoring quadratic trinomials? For me, it's the AC method with grouping because there's no guess and check, which frustrated me as a high school student. I remember endlessly erasing my work, and settling with "close enough" on some problems. The box, or area, method has grown on me over the years, especially how it links back to multiplying polynomials.
The structure of the AC method works for me, and is the method I have used most when teaching students to factor. I don't know when I learned it, but I remember thinking that it would have been a helpful tool for me in high school. If making the list of factors is difficult, students can divide AC with 2, 3, 4, ... with a calculator and write down any quotients without decimals, checking which factor pair adds to B.
I made a couple factoring quadratics cheat sheets and posted them on Facebook this week.
We're getting to factoring in a few weeks after imaginary number operations, Quadratic Formula and solving with square roots and we're going to teach the kids the box (area) method, which they may have seen in algebra 1. AC with grouping will be the backup plan for students who aren't clicking with the box method. Multiplication charts will also be available to students who need them.
Box method factoring
AC method with grouping
If you are teaching factoring this year, I wanted to share the two cheat sheets above in case you find them helpful. I also wanted to mention that the cheat sheets I share are never intended to be standalone teaching tools. They always go along with lessons as a way to help students through independent work. This was something that came up this week, too.
A teacher recently requested box method factoring references be added to the algebra word wall, so I added these two posters.
> Browse all Quadratics activities
You can download the two factoring cheat sheets free here.
For practice, there's a free set of solve by factoring task cards here.
> Browse all free math cheat sheets
