Question

помогите пожалуйста
30 баллов даю​

Answer 1

Ответ:

$\left \{ {{x=4-y} \atop {-x+2y+1=0}} \right. \left \{ {{x=4-y} \atop {-(4-y)+2y+1=0}} \right. \left \{ {{x=4-y} \atop {-4+y+2y+1=0}} \right. \left \{ {{x=4-y} \atop {3y-3=0}} \right. \left \{ {{x=4-y} \atop {3y=3}} \right. \left \{ {{x=4-1} \atop {y=1}} \right. \left \{ {{x=3} \atop {y=1}} \right.$