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9x^2+52y^2-36x+50y-164=0 canonical form

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                 2              2    
-164 - 36*x + 9*x  + 50*y + 52*y  = 0
$$9 x^{2} - 36 x + 52 y^{2} + 50 y - 164 = 0$$
9*x^2 - 36*x + 52*y^2 + 50*y - 164 = 0
Detail solution
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
$$\vec e_1 = \left( 1, \ 0\right)$$
$$\vec e_2 = \left( 0, \ 1\right)$$
Invariants method
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
$$a_{11} = 9$$
$$a_{12} = 0$$
$$a_{13} = -18$$
$$a_{22} = 52$$
$$a_{23} = 25$$
$$a_{33} = -164$$
The invariants of the equation when converting coordinates are determinants:
$$I_{1} = a_{11} + a_{22}$$
     |a11  a12|
I2 = |        |
     |a12  a22|

$$I_{3} = \left|\begin{matrix}a_{11} & a_{12} & a_{13}\\a_{12} & a_{22} & a_{23}\\a_{13} & a_{23} & a_{33}\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}a_{11} - \lambda & a_{12}\\a_{12} & a_{22} - \lambda\end{matrix}\right|$$
     |a11  a13|   |a22  a23|
K2 = |        | + |        |
     |a13  a33|   |a23  a33|

substitute coefficients
$$I_{1} = 61$$
     |9  0 |
I2 = |     |
     |0  52|

$$I_{3} = \left|\begin{matrix}9 & 0 & -18\\0 & 52 & 25\\-18 & 25 & -164\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}9 - \lambda & 0\\0 & 52 - \lambda\end{matrix}\right|$$
     | 9   -18 |   |52   25 |
K2 = |         | + |        |
     |-18  -164|   |25  -164|

$$I_{1} = 61$$
$$I_{2} = 468$$
$$I_{3} = -99225$$
$$I{\left(\lambda \right)} = \lambda^{2} - 61 \lambda + 468$$
$$K_{2} = -10953$$
Because
$$I_{2} > 0 \wedge I_{1} I_{3} < 0$$
then by line type:
this equation is of type : ellipse
Make the characteristic equation for the line:
$$- I_{1} \lambda + I_{2} + \lambda^{2} = 0$$
or
$$\lambda^{2} - 61 \lambda + 468 = 0$$
$$\lambda_{1} = 52$$
$$\lambda_{2} = 9$$
then the canonical form of the equation will be
$$\tilde x^{2} \lambda_{1} + \tilde y^{2} \lambda_{2} + \frac{I_{3}}{I_{2}} = 0$$
or
$$52 \tilde x^{2} + 9 \tilde y^{2} - \frac{11025}{52} = 0$$
$$\frac{\tilde x^{2}}{\left(\frac{\frac{1}{26} \sqrt{13}}{\frac{2}{105} \sqrt{13}}\right)^{2}} + \frac{\tilde y^{2}}{\left(\frac{1}{3 \frac{2 \sqrt{13}}{105}}\right)^{2}} = 1$$
- reduced to canonical form