#[Common factor][Factor común]#
A
common factor is a term that occurs as a factor in each of the expressions being added or subtracted. For example, $x$ is a common factor in $2x^2 + x,$ since it is a factor of both $2x^2$ and $x.$ On the other hand, $x^2$ is not a common factor, since it is not a factor of the second term, $x.$