x^2/m^2+y^2/n^2=1
代入
9/(4m^2)+25/(4n^2)=1 (1)
3/m^2+5/n^2=1 (2)
(1)-3/4*(2)
25/(4n^2)-15/(4n^2)=1-3/4
10/(4n^2)=1/4
n^2=10,m^2=6
所以x^2/6+y^2/10=1