Given line equation of 2-order:
$$9 x^{2} - 36 x + 52 y^{2} + 50 y - 164 = 0$$
This equation looks like:
$$a_{11} x^{2} + 2 a_{12} x y + 2 a_{13} x + a_{22} y^{2} + 2 a_{23} y + a_{33} = 0$$
where
$$a_{11} = 9$$
$$a_{12} = 0$$
$$a_{13} = -18$$
$$a_{22} = 52$$
$$a_{23} = 25$$
$$a_{33} = -164$$
To calculate the determinant
$$\Delta = \left|\begin{matrix}a_{11} & a_{12}\\a_{12} & a_{22}\end{matrix}\right|$$
or, substitute
$$\Delta = \left|\begin{matrix}9 & 0\\0 & 52\end{matrix}\right|$$
$$\Delta = 468$$
Because
$$\Delta$$
is not equal to 0, then
find the center of the canonical coordinate system. To do it, solve the system of equations
$$a_{11} x_{0} + a_{12} y_{0} + a_{13} = 0$$
$$a_{12} x_{0} + a_{22} y_{0} + a_{23} = 0$$
substitute coefficients
$$9 x_{0} - 18 = 0$$
$$52 y_{0} + 25 = 0$$
then
$$x_{0} = 2$$
$$y_{0} = - \frac{25}{52}$$
Thus, we have the equation in the coordinate system O'x'y'
$$a'_{33} + a_{11} x'^{2} + 2 a_{12} x' y' + a_{22} y'^{2} = 0$$
where
$$a'_{33} = a_{13} x_{0} + a_{23} y_{0} + a_{33}$$
or
$$a'_{33} = - 18 x_{0} + 25 y_{0} - 164$$
$$a'_{33} = - \frac{11025}{52}$$
then equation turns into
$$9 x'^{2} + 52 y'^{2} - \frac{11025}{52} = 0$$
Given equation is ellipse
$$\frac{\tilde x^{2}}{\left(\frac{1}{3 \frac{2 \sqrt{13}}{105}}\right)^{2}} + \frac{\tilde y^{2}}{\left(\frac{\frac{1}{26} \sqrt{13}}{\frac{2}{105} \sqrt{13}}\right)^{2}} = 1$$
- reduced to canonical form
The center of canonical coordinate system at point O
-25
(2, ----)
52
Basis of the canonical coordinate system
$$\vec e_1 = \left( 1, \ 0\right)$$
$$\vec e_2 = \left( 0, \ 1\right)$$