[tex]\left\{\begin{array}{ccc}-5x-8y=17\\2x-7y=-17\end{array}\right\\\left\{\begin{array}{ccc}-5x=8y+17&/\cdot(-2)\\2x-7y=-17&/\cdot5\end{array}\right\\\\\left\{\begin{array}{ccc}10x=-16y-34\\10x-35y=-85\end{array}\right\\\\substitute:\\\\-16y-34-35y=-85\\-51y=-85+34\\-51y=-51\ \ \ \ /:(-51)\\y=1\\\\10x=-16\cdot1-34\\10x=-50\ \ \ \ /:10\\x=-5\\\\Solution:x=-5\ and\ y=1[/tex]