Incorrect. A common denominator for these fractions is $\displaystyle{12}{\left({x}+{3}\right)}\usepackage{cmbright}\Huge\$ . Multiplying both sides by this expression, he finds $\displaystyle{12}{\left({x}+{3}\right)}\cdot{\left(\frac{{3}}{{{x}+{3}}}\right)}={12}{\left({x}+{3}\right)}\cdot\frac{{{9}{x}}}{{12}}\usepackage{cmbright}\Huge\$ . What does this equation simplify to?