Question

$left { {{x+3y=0} atop { x^{2} + y^{2}-2yx=9 }} right.$

Answer 1

$left { {{x+3y=0} atop {x^2+y^2-2xy=9}} right. == textgreater left { {{x+3y=0} atop {(x-y)^2=9}} right. == textgreater left { {{x+3y=0} atop {x-y=+-3}} right.$

{x+3y=0
{x-y=3      =>x=3+y
3+y+3y=0
4y=-3
y=-3/4

x=3+y
x=9/4

{x+3y=0
{x-y=-3      x=y-3
y-3+3y=0
4y=3
y=3/4

x=y-3
x=-3/4

x1=9/4; x2=-3/4
y1=-3/4;  y2=3/4

Answer 2

спасибо

Answer 3

пожалуйста)