Read the page until the section titled "Example: 'Factor by Grouping' Method." Try factoring trinomials using this method: click on the "new problem" button at the end of the page to try a practice problem. After answering the problem, click on the "check your answer" button. Continue this process by clicking on "new problem," and solve five problems. You can also create a worksheet of five problems by clicking on the button at the bottom of the page titled "Click Here for a Randomly Generated Worksheet and Answers." The answers will be provided at the end of the worksheet.
While Dr. Burns points out in this reading that listing all trial factors and checking their products can be tedious, some trinomials can be factored fairly quickly using this method. For example, if either a or c or both are prime, their only factors are 1 and itself, and this limits the number of trial factors. Also, if c is positive, both binomial factors will have to contain the same sign, and this limits the number of trial factors as well.