Tomamos como el límite
$$\lim_{x \to a^+}\left(\frac{- x \left(a + 1\right) + \left(a + x^{2}\right)}{- a^{3} + x^{5}}\right)$$
cambiamos
$$\lim_{x \to a^+}\left(\frac{- x \left(a + 1\right) + \left(a + x^{2}\right)}{- a^{3} + x^{5}}\right)$$
=
$$\lim_{x \to a^+}\left(\frac{\left(- a + x\right) \left(x - 1\right)}{- a^{3} + x^{5}}\right)$$
=
$$\lim_{x \to a^+}\left(\frac{\left(a - x\right) \left(x - 1\right)}{a^{3} - x^{5}}\right) = $$
$$\frac{\left(- a + a\right) \left(a - 1\right)}{- a^{5} + a^{3}} = $$
= 0
Entonces la respuesta definitiva es:
$$\lim_{x \to a^+}\left(\frac{- x \left(a + 1\right) + \left(a + x^{2}\right)}{- a^{3} + x^{5}}\right) = 0$$