EDGE Math 8

Factoring Other Trinomials

Trinomials in the Form $a x^{2} + b x + c$

Two techniques for factoring trinomials in the form $a x^{2} + b x + c$ will be presented in this lesson.

The first method uses the FOIL method to get the product of two binomials. For example, to factor $2 x^{2} + x - 15,$ you need to find the missing integers in the equation below that will make the equation true.

Using the FOIL method on the right-hand side of the equation, you can say that the F product should have 2 as coefficient, the sum of the O product coefficient and the I product coefficient should be 1, and the L product coefficient should be $- 15 .$

Since the F product has a positive coefficient 2 and the only positive factors of 2 are 2 and 1, the blanks for the first terms of the binomial factors should be filled up as follows:

(Continued in the next slide)