Correct. The first pair of terms has a GCF $\displaystyle{6}{m}\usepackage{cmbright}\Huge\$ and the second pair has a GCF 5:

$\displaystyle{6}{m}{n}+{12}{m}+{5}{n}+{10}={6}{m}{\left({n}+{2}\right)}+{5}{\left({n}+{2}\right)}={\left({n}+{2}\right)}{\left({6}{m}+{5}\right)}\usepackage{cmbright}\Huge\$

So $\displaystyle{6}{m}\usepackage{cmbright}\Huge\$ is the missing term.