Incorrect. The common denominator is $\displaystyle{2}{x}{y}\usepackage{cmbright}\Huge\$ . Rewrite each fraction so that it has this denominator:

$\displaystyle\frac{{3}}{{{2}{x}}}+\frac{{5}}{{y}}=\frac{{3}}{{{2}{x}}}\cdot\frac{{y}}{{y}}+\frac{{5}}{{y}}\cdot\frac{{{2}{x}}}{{{2}{x}}}\usepackage{cmbright}\Huge\$

Multiply, and then add the numerators.