This is not an elliptic problem, it may be a hyperbola, or it may not be. It should be like this -AB = 1, then the equation can be a (x 2-y 2)+y 2 = 1 observation equation. If you want to pass the fixed point, you must first eliminate the unknown number A. As long as x 2-y 2 = 0. Thus, x 2 = y 2 =1passes through four fixed points. So is the other one. Over.