Объяснение:

[tex]\left \{ {{3x-y=11} \atop {5x+6y=26}} \right. \ \ \ \ \ \left \{ {{y=3x-11} \atop {5x+6*(3x-11)=26}} \right.\ \ \ \ \left \{ {{y=3x-11} \atop {5x+18x-66=26}} \right.\ \ \ \ \ \left \{ {{y=3x-11} \atop {23x=92\ |:23}} \right. \ \ \ \ \left \{ {{y=1} \atop {x=4}} \right. .\\[/tex]

Ответ: (4;1).