Х+игрик=5 х2+игрик2=25

Решите задачу:

$\left \{ {{x+y=5} \atop {x^2+y^2=25}} \right. \; \left \{ {{(x+y)^2=5^2} \atop {x^2+y^2=25}} \right. \; \left \{ {{x^2+y^2+2xy=25} \atop {x^2+y^2=25}} \right. \; \left \{ {{25+2xy=25} \atop {x^2+y^2=25}} \right. \; \left \{ {{2xy=0} \atop {x^2+y^2=25}} \right. \\\\ \left \{ {{x=0\; ili\; y=0} \atop {x^2+y^2=25}} \right.\; \to \\\\a)\; \; \left \{ {{x=0} \atop {x^2+y^2=25}} \right. \; \; ili\; \; b)\; \left \{ {{y=0} \atop {x^2+y^2=25}} \right. \\\\ \left \{ {{x=0} \atop {y^2=25}} \right.$

$\left \{ {{x=0} \atop {y=\pm 5}} \right. \\\\b) \left \{ {{y=0} \atop {x^2=25}} \right. \; \left \{ {{y=0} \atop {x=\pm 5}} \right. \\\\Otvet:\; (0;-5),\; (0;5),\; (-5;0),\; (5;0).$