Question

решить 3, только под номером 3​

Answer 1

$\left \{ {{2x-y=-1} \atop {x+y=7}} \right.\\ \left \{ {{x=7-y} \atop {2(y-7)-y=-1}} \right. \\\left \{ {{x=7-y} \atop 14-2y-y+1=0}} \right. \\\left \{ {{x=7-y} \atop -3y+15=0}} \right.\\\left \{ {{x=7-y} \atop {-3y=-15}} \right. \\\left \{ {{x=7-y} \atop {y=\frac{-15}{-3} }} \right.\\\left \{ {{x=7-y} \atop {y=\frac{-15}{-3} }} \right.\\\left \{ {{x=7-5} \atop {y=5}} \right. \\\left \{ {{x=2} \atop {y=5}} \right.$

Ответ: 5; 2.