[tex]\displaystyle \left \{ {{x-7y=36} \atop {9x+4y=-11}} \right. \\\\\left \{ {{x=36+7y} \atop {9x+4y=-11}} \right. \\\\9(36+7y)+4y=-11\\y=-5\\x=36+7(-5)\\x=1\\(x,y)=(1,-5)[/tex]