Tomamos como el límite
$$\lim_{x \to 0^+}\left(\frac{x^{2}}{- x^{2} + \left(8 - \sqrt{6}\right)}\right)$$
cambiamos
$$\lim_{x \to 0^+}\left(\frac{x^{2}}{- x^{2} + \left(8 - \sqrt{6}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{x^{2}}{- x^{2} - \sqrt{6} + 8}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{x^{2}}{x^{2} - 8 + \sqrt{6}}\right) = $$
$$- \frac{0^{2}}{-8 + 0^{2} + \sqrt{6}} = $$
= 0
Entonces la respuesta definitiva es:
$$\lim_{x \to 0^+}\left(\frac{x^{2}}{- x^{2} + \left(8 - \sqrt{6}\right)}\right) = 0$$