Question

$\left \{ {{x+y=1} \atop { x^{2 + y^{2} =25}} \right.$

Answer 1

$\left \{ {{x+y=1} \atop {x^2+y^2=25}} \right. =>\left \{ {{x=1-y} \atop {x^2+y^2=25}} \right. =>(1-y)^2+y^2=25=>y^2-y-12=0\\D=1+48=49\\y_1=4\\y_2=-3\\x_1=-3\\x_2=4$

Ответ:$(x_1;y_1)=(-3;4)\\(x_2;y_2)=(4;-3)$