Circle

$3 x^2-8 x y+3 y^2-2 x-2 y+6=0$

$11 x^2-8 x y+11 y^2-4 x-4 y-6=0$

$3 x^2-8 x y+3 y^2+2 x+2 y-2=0$

$x^2-4 x y+y^2+x+y=0$