Если (x,y)-решение системы уравнений, то x·y равно

[latex] \left \{ {{11x+27y=-1} \atop {13x+23y=-19}} \right. \; (#2yravnenie-#1yravnenie) \\\\\left \{ {{2x-4y=-18|:2} \atop {11x+27y=-1}} \right. \; \left \{ {{x=2y-9} \atop {11(2y-9)+27y=-1}} \right. \; \left \{ {{x=2y-9} \atop {49y=98}} \right. \; \left \{ {{x=-5} \atop {y=2}} \right. [/latex] xy=-10