Incorrect. 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)}\usepackage{cmbright}\Huge\$

The two resulting terms have a common factor. Factor this out to complete the factorization.