6.
Factor out the greatest common factor. The biggest number that
goes into all of the coefficients is 6. All of the terms have at least one
factor of a and one factor of b. Factor out a 6ab
We can tell that we have factored out the greatest common
factor because there is no common factor for the terms in the
parentheses.
At this point we see if there is some other way that the
expression inside the parentheses can be factored in any other way,
but it cannot.