This is a factorization of the given expression, but $\displaystyle{3}{c}\usepackage{cmbright}\Huge\$ is not the GCF. You may have thought that you needed only to factor out the different factors that occur. However, they have the variable c in common five times, so $\displaystyle{{c}}^{{5}}\usepackage{cmbright}\Huge\$ is part of the GCF, and they have the prime 2 in common one time and the prime 3 in common two times, so $\displaystyle{2}\cdot{{3}}^{{2}}\usepackage{cmbright}\Huge\$ or 18 is part of the GCF.