From the point (-1, -1), two rays are sent making angles of 45° with the line x+y=0. These rays get reflected from the mirror x+2 y=1. If the…

From the point $\displaystyle (-1, -1)$, two rays are sent making angles of $\displaystyle 45$° with the line $\displaystyle x+y=0$. These rays get reflected from the mirror $\displaystyle x+2 y=1$. If the equations of the reflected rays are $\displaystyle \mathrm{a} x+\mathrm{b} y=9$ and $\displaystyle \mathrm{c} x+\mathrm{d} y=7, \mathrm{a}, \mathrm{b}, \mathrm{c}, \mathrm{d} \in \mathbf{Z}$, then the value of $\displaystyle \mathrm{ad}+\mathrm{bc}$ is $\displaystyle \_\_\_\_$.