Решите систему уравнения: {х+Зу=13, {7х-4у=-34.

[latex] \left \{ {{x+3y=13} \atop {7x-4y=-34}} \right. [/latex] [latex] \left \{ {{x=13-3y} \atop {7x-4y=-34}} \right. [/latex] [latex]7(13-3y)-4y=-34[/latex] [latex]91-21y-4y+34=0[/latex] [latex]-25y=-125[/latex] [latex]y=5[/latex] [latex]x=13-3*5=-2[/latex] ответ:(5;-2)