5x2 + 9y2 –2·7·x + 18y + 9 = 0.
(5x^2 –2·7·x )+ (9y^2 + 18y + 9) = 0.
5(x^2-(14/5)x)+9(x^2+2y+1)=0
5(x-7/5)^2+9(y+1)^2=49/5
Делим уравнение на (49/5)
(25/49)(x-7/5)^2+(45/49)(y+1)^2=1
(x-7/5)^2/(49/25)+(y+1)^2/(49/45) =1
координаты центра и полуоси эллипса
[b](7/5; -1)[/b]
a^2=49/25
[b]a=7/5[/b]
b^2=49/45
[b]b=7/(3sqrt(5))[/b]