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4x^2+25y^2-16x+50y-67=0 canonical form

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                2       2           
-67 - 16*x + 4*x  + 25*y  + 50*y = 0
$$4 x^{2} - 16 x + 25 y^{2} + 50 y - 67 = 0$$
4*x^2 - 16*x + 25*y^2 + 50*y - 67 = 0
Detail solution
Given line equation of 2-order:
$$4 x^{2} - 16 x + 25 y^{2} + 50 y - 67 = 0$$
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
$$a_{11} = 4$$
$$a_{12} = 0$$
$$a_{13} = -8$$
$$a_{22} = 25$$
$$a_{23} = 25$$
$$a_{33} = -67$$
To calculate the determinant
$$\Delta = \left|\begin{matrix}a_{11} & a_{12}\\a_{12} & a_{22}\end{matrix}\right|$$
or, substitute
$$\Delta = \left|\begin{matrix}4 & 0\\0 & 25\end{matrix}\right|$$
$$\Delta = 100$$
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
$$4 x_{0} - 8 = 0$$
$$25 y_{0} + 25 = 0$$
then
$$x_{0} = 2$$
$$y_{0} = -1$$
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
$$a'_{33} = - 8 x_{0} + 25 y_{0} - 67$$
$$a'_{33} = -108$$
then equation turns into
$$4 x'^{2} + 25 y'^{2} - 108 = 0$$
Given equation is ellipse
$$\frac{\tilde x^{2}}{\left(\frac{1}{2 \frac{\sqrt{3}}{18}}\right)^{2}} + \frac{\tilde y^{2}}{\left(\frac{1}{5 \frac{\sqrt{3}}{18}}\right)^{2}} = 1$$
- reduced to canonical form
The center of canonical coordinate system at point O
(2, -1)

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:
$$4 x^{2} - 16 x + 25 y^{2} + 50 y - 67 = 0$$
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
$$a_{11} = 4$$
$$a_{12} = 0$$
$$a_{13} = -8$$
$$a_{22} = 25$$
$$a_{23} = 25$$
$$a_{33} = -67$$
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
$$I_{1} = 29$$
     |4  0 |
I2 = |     |
     |0  25|

$$I_{3} = \left|\begin{matrix}4 & 0 & -8\\0 & 25 & 25\\-8 & 25 & -67\end{matrix}\right|$$
$$I{\left(\lambda \right)} = \left|\begin{matrix}4 - \lambda & 0\\0 & 25 - \lambda\end{matrix}\right|$$
     |4   -8 |   |25  25 |
K2 = |       | + |       |
     |-8  -67|   |25  -67|

$$I_{1} = 29$$
$$I_{2} = 100$$
$$I_{3} = -10800$$
$$I{\left(\lambda \right)} = \lambda^{2} - 29 \lambda + 100$$
$$K_{2} = -2632$$
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
$$\lambda^{2} - 29 \lambda + 100 = 0$$
$$\lambda_{1} = 25$$
$$\lambda_{2} = 4$$
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
$$25 \tilde x^{2} + 4 \tilde y^{2} - 108 = 0$$
$$\frac{\tilde x^{2}}{\left(\frac{1}{5 \frac{\sqrt{3}}{18}}\right)^{2}} + \frac{\tilde y^{2}}{\left(\frac{1}{2 \frac{\sqrt{3}}{18}}\right)^{2}} = 1$$
- reduced to canonical form