Correct. You recognized that $\displaystyle\frac{{{4}{{x}}^{{2}}-{144}}}{{{2}{{x}}^{{2}}-{24}{x}+{72}}}=\frac{{{4}{\left({{x}}^{{2}}-{36}\right)}}}{{{2}{\left({{x}}^{{2}}-{12}{x}+{36}\right)}}}=\frac{{{4}{\left({x}+{6}\right)}{\left({x}-{6}\right)}}}{{{2}{\left({x}-{6}\right)}{\left({x}-{6}\right)}}}\usepackage{cmbright}\Huge\$ . Pulling out factors of 1 leaves you with the simplified expression $\displaystyle\frac{{{2}{\left({x}+{6}\right)}}}{{{\left({x}-{6}\right)}}}\usepackage{cmbright}\Huge\$ .