Question

x^2+y^2+2xy=9, x-y=1 решить систему методом сложения

Answer 1

$left { {{x^2+y^2+2xy=9} atop {x-y=1}} right. ; left { {{(x+y)^2=9} atop {x-y=1}} right. ; left { {{x+y=pm 3} atop {x-y=1}} right. \\a); ; left { {{x+y=3} atop {x-y=1}} right. ; oplus ; left { {{x+y=3} atop {2x=4}} right. ; left { {{y=3-x} atop {x=2}} right. ; left { {{y=1} atop {x=2}} right.$

$b); ; left { {{x+y=-3} atop {x-y=1}} right. ; oplus left { {{x+y=-3} atop {2x=-2}} right. left { {{y=-3-x} atop {x=-1}} right. ; left { {{y=-2} atop {x=-1}} right.$

$Otvet:; ; (2,1); ,; ; (-1,-2); .$