Odpowiedź:
C czyli I i III
Szczegółowe wyjaśnienie:
I
[tex]\\\left \{ {{x-5y=-14} \atop {2x+3y=-2}} \right. \\\left \{ {{x=5y-14} \atop {2x+3y=-2}} \right. \\\\2(5y-14)+3y=-2\\10y-28+3y=-2\\13y=-2+28\\13y=26/13\\y=2\\\\x-5*2=-14\\x-10=-14\\x=-14+10\\x=-4\\\\x=-4\\y=2[/tex]
II
[tex]\left \{ {{-x=y+2} \atop {0=2x-y-10}} \right. \\\left \{ {{-x=y+2} \atop {y=2x-10}} \right. \\-x=2x-10+2\\-x-2x=-8\\-3x=-8/(-3)\\x=\frac{8}{3} =2\frac{2}{3} \\\\-2\frac{2}{3} =y+2\\-y=2+2\frac{2}{3} \\-y=4\frac{2}{3} /(-1)\\y =-4\frac{2}{3} \\\\x=2\frac{2}{3}\\y=-4\frac{2}{3}\\[/tex]
III
[tex]\left \{ {{-3x+2y=16} \atop {x+4=y-2}} \right. \\\left \{ {{-3x+2y=16} \atop {x=y--4}} \right. \\\left \{ {{-3x+2y=16} \atop {x=y-6}} \right. \\-3(y-6)+2y=16\\-3y+18+2y=16\\-y=16-18\\-y=-2/(-1)\\y=2\\\\-3x+2*2=16\\-3x+4=16\\-3x=16-4\\-3x=12/(-3)\\x=-4\\\\x=-4\\y=2[/tex]
