Фигурная скобка х+2у=5 -х+7у=13

[latex] \left \{ {{x=5-2y} \atop {-(5-2y)+7y=13}} \right. [/latex] [latex] \left \{ {{x=5-2y} \atop {-5+2y+7y=13}} \right. [/latex] [latex] \left \{ {{x=5-2y} \atop {9y=18}} \right. [/latex] [latex] \left \{ {{x=5-2*2} \atop {y=2}} \right. [/latex] [latex] \left \{ {{x=1} \atop {y=2}} \right. [/latex]