You may have correctly substituted 2 for $\displaystyle{y}\usepackage{cmbright}\Huge\$ and gotten $\displaystyle{9}{\left({6}-{2}\right)}\usepackage{cmbright}\Huge\$ , but then interpreted this incorrectly as $\displaystyle{9}{\left({6}\right)}-{2}\usepackage{cmbright}\Huge\$ . Using the distributive property, $\displaystyle{9}{\left({6}-{2}\right)}\usepackage{cmbright}\Huge\$ is correctly rewritten as $\displaystyle{9}{\left({6}\right)}-{9}{\left({2}\right)}\usepackage{cmbright}\Huge\$ . The correct answer is 36.