1)设双曲线方程为：x^2/a^2-y^2/b^2=1 49/a^2-72/b^2=1 (1) 28/a^2-9/b^2=1 (2)
8*(2)-(1) 175/a^2=7 a^2=25代入(2) 28/25-9/b^2=1 9/b^2=3/25 b^2=75
双曲线标准方程：x^2/25-y^2/75=1
2)设双曲线方程为：y^2/a^2-x^2/b^2=1 72/a^2-49/b^2=1 (3) 9/a^2-28/b^2=1 (4)
(3)-8*(4) 175/b^2=-7不合题意.
所以,所求双曲线标准方程为：x^2/25-y^2/75=1