不能确定焦点,先设标准方程为:x^2/a^2-y^2/b^2=1,
(-7)^2/a^2-(-6√2)^2/b^2=1,
49/a^2-72/b^2=1.(1),
28/a^2-9/b^2=1.(2),
(2)式*8-(1)式
175/a^2=7,
a^2=25,
a=5,
代入(2)式,5√3,
双曲线方程为:x^2/25-y^2/75=1,
再设双曲线方程为y^2/b^2-x^2/a^2=1,
72/b^2-49/a^2=1.(3),
9/b^2-28/a^2=1.(4),
(3)式-(4)式*8,
175/a^2=-7,
a^2=-25,
没有实根,故焦点不在Y轴.
∴双曲线方程为:
x^2/25-y^2/75=1.