Two circles each of radius 5 units touch each other at the point $(1,2)$. If the equation of their common tangent is $4 \mathrm{x}+3 \mathrm{y}=10$, and $\mathrm{C}_1(\alpha, \beta)$ and $\mathrm{C}_2(\gamma, \delta), \mathrm{C}_1 \neq \mathrm{C}_2$ are their centres, then $|(\alpha+\beta)(\gamma+\delta)|$ is equal to $\_\_\_\_$ .