Question

система x + y = 15 на
                 xy = 56

Answer 1

X=15-y
Y(15-y)=56
15y-y^2-56=0
Y^2-15y+56=0
D=225-224=1
y1=14/2=7;y2=16/2=8
X1=15-7=8;x2=15-8=7