Question

решить систему уравнений x+y=3
x^2+y^2=25+2xy

Answer 1

$x+y=3\ x^2+y^2-2xy=25\ \ x+y=3\ (x-y)^2=25\ \ x+y=3\ x-y=5\ \ 3-y=5+y\ -2=2y\ y=-1\ x=4\ \ x+y=3\ x-y=-5\ 3-y=y-5\ 8=2y\ y=4\ x=-1$