x-a 2- y-b 2 r2, x-a 2+ y-b 2 0, x-r 2 + y-r 2 r 2, x 2 - y 2, x 2/a-y 2/b 1, x 2/a 2-y 2/b 2 1, x 2-xy-y 2, x/a+y/b 2, x -b/2a y, x2/a2+y2/b2 r2, y x 2/2r, y2/a2-x2/b2 1
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