Rewrite $m^{4}-49$ as $\left(m^{2}\right)^{2}-7^{2}$. The difference of squares can be factored using the rule: $a^{2}-b^{2}=\left(a-b\right)\left(a+b\right)$. The following polynomials are not factored since they do not have any rational roots: $m^{2}-7,m^{2}+7$.
