Factoring a GCF first

Sometimes a trinomial has a greatest common factor.  When this is the case, we should first factor that, and then apply reverse FOIL.

Example 6:  Factor 6x² – 2x – 4

Solution: Every term is a multiple of 2.  That is, 2 is a greatest common factor, so we first factor that:

6x² – 2x – 4 = 2(3x² – x – 2)

Then we factor the trinomial in parentheses:

6x² – 2x – 4 = 2(3x² – x – 2) = 2(3x + 2)(x – 1)

toc | return to top | previous page | next page