Find the equation of the tangent and normal at (-1,2) on the ellipse ${\mathrm{x}}^2+8{\mathrm{y}}^2=33$

$Given ellipse x^2+8y^2=33 and the point (-1,2)$

Equation of  tangent is $S_1=0$
$\begin{array}{l}\Rightarrow \mathrm{x}(-1)+8\mathrm{y}\left(2\right)=33\\ \Rightarrow -\mathrm{x}+16\mathrm{y}=33\Rightarrow \mathrm{x}-16\mathrm{y}+33=0\end{array}$
Equation of the normal is $16\mathrm{x}+\mathrm{y}+\mathrm{K}=0$  

Since it passes through P(–1,2) then
$-16+2+\mathrm{K}=0\Rightarrow \mathrm{K}=14$
Equation of the normal is 16x + y +14 = 0