Question

Помогите !!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

$left { {{x^2+y^2=25} atop {x+y=7}} right. \ \ x=7-y \ \ (7-y)^2+y^2=25 \ 49-14y+y^2+y^2=25 \ 2y^2-14y+24=0 \ y^2-7y+12=0 \ D=b^2-4ac=1 \ y_1_,_2= frac{-b^+_- sqrt{D} }{2a} \ y_1=3 \ y_2=4 \ \ x_1=7-3=4 \ x_2=7-4=3$