[tex]zad.a\\\\\left \{ {{x+y=-4} \atop {2x+y=-5}} \right. \\\\\left \{ {{y=-4-x} \atop {2x-4-x=-5}} \right. \\\\\left \{ {{y=-4-x} \atop {x=-5+4}} \right. \\\\\left \{ {{x=-1} \atop {y=-4-(-1)}} \right. \\\\\left \{ {{x=-1} \atop {y=-4+1}} \right.\\\\\left \{ {{x=-1} \atop {y=-3}} \right. \\\\Sprawdzam:\\\\\left \{ {{-1+(-3)=-4} \atop {2\cdot (-1)+(-3)=-5}} \right. \\\\\left \{ {{-1-3=-4} \atop {-2-3=-5}} \right. \\\\\left \{ {{-4=-4} \atop {-5=-5}} \right. \\\\[/tex]
[tex]\left \{ {{L=P} \atop {L=P}} \right. ~~~~~~cbdu[/tex]
[tex]zad.b\\\\\left \{ {{x+2y=-1} \atop {x-y=-4}} \right. \\\\\left \{ {{x=-1-2y} \atop {x-y=-4}} \right. \\\\\left \{ {{x=-1-2y} \atop {-1-2y-y=-4}} \right. \\\\\left \{ {{x=-1-2y} \atop {-3y=-4+1}} \right. \\\\\left \{ {{x=-1-2y} \atop {-3y=-3 ~~\mid~~\div (-3)}} \right. \\\\\left \{ {{y=1} \atop {x=-1-2\cdot 1}} \right. \\\\\left \{ {{y=1} \atop {x=-1-2}} \right. \\\\\left \{ {{y=1} \atop {x=-3}} \right. \\\\Sprawdzam:\\\\\left \{ {{-3+2\cdot 1=-1} \atop {-3-1=-4}} \right. \\\\[/tex]
[tex]\left \{ {{-3+2=-1} \atop {-4=-4}} \right. \\\\\left \{ {{-1=-1} \atop {-4=-4}} \right. \\\\\left \{ {{L=P} \atop {L=P}} \right. ~~~~cbdu[/tex]
