Correct. After multiplying both sides of the equation by the common denominator $\displaystyle{\left({12}+{y}\right)}{\left({6}+{y}\right)}\usepackage{cmbright}\Huge\$ , you find $\displaystyle{9}{\left({6}+{y}\right)}-{3}{\left({12}+{y}\right)}={54}+{9}{y}-{36}-{3}{y}={6}{y}+{18}={0}\usepackage{cmbright}\Huge\$ , so $\displaystyle{y}=-{3}\usepackage{cmbright}\Huge\$ .