Thermodynamics

The $\Delta_{f} H^{\theta}$ of $\mathrm{AO}(s), \mathrm{BO}_{2}(g)$ and $A B \mathrm{O}_{3}(s)$ is $-635, x$ and $-1210 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. $\left.\mathrm{ABO}_{3}(s) \rightarrow \mathrm{AO}(s)+\mathrm{BO}_{2}(g): \Delta_{r} H^{\Theta}=175 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)$. What is the value of $x$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ )?