Thermodynamics

Calculate heat of formation of $\mathrm{SO}_2$ from following equations.

$$ \begin{aligned} & \mathrm{S}+\frac{3}{2} \mathrm{O}_2 \longrightarrow \mathrm{SO}_3, \Delta \mathrm{H}=-2 \mathrm{xkJ} \\ & \mathrm{SO}_2+\frac{1}{2} \mathrm{O}_2 \longrightarrow \mathrm{SO}_3, \Delta \mathrm{H}=-\mathrm{ykJ} \end{aligned} $$