**FACTORING:**
__Factoring__ is the “undoing” of multiplication, putting an

expression into terms which are multiplied. For example, we know that 6x(x

^{3} – 7) = 6x

^{4} – 42x.

- The expression 6x
^{4} – 42x __factors__ into two terms which are multiplied: 6x•(x^{3} – 7)

- The
__difference of two squares__ such as x^{2}- 49 factors into (x+7)•(x-7)

- Sometimes
__trinomials__ factor very nicely:

Sometimes they do not. The

trinomial x

^{2} + x + 1 defies a simple factoring.