x^2-y^2-4x+2y-3=0
(x-2)^2-(y-1)^2=6
(x-2)^2/6-(y-1)^2/6=1 (双曲线)
关于原点对称的曲线
(x+2)^2/6-(y+1)^2=6
即(x+2)^2-(y+1)^2=6 (双曲线)