Răspuns:
x=3 si y=-3
Explicație pas cu pas:
[tex]\left \{ {{x+2y=-3} \atop {4x+y=9}} \right\\\left \{ {{x=-3-2y} \atop {4(-3-2y)+y=9}} \right. \\\\left \{ {{x=-3-2y} \atop {-12-8y+y=9}} \right. \\\left \{ {{x=-3-2y} \atop {-7y=9+12}} \right. \\\left \{ {{x=-3-2y} \atop {-7y=21}} \right. \\\left \{ {{y=-3} \atop {x=-3-2*(-3)}} \right. \\\left \{ {{y=-3} \atop {x=3}} \right.[/tex]
