Tomamos como el límite
$$\lim_{x \to 1^+}\left(\frac{x^{2} + 11}{- x + \left(x^{2} - 12\right)}\right)$$
cambiamos
$$\lim_{x \to 1^+}\left(\frac{x^{2} + 11}{- x + \left(x^{2} - 12\right)}\right)$$
=
$$\lim_{x \to 1^+}\left(\frac{x^{2} + 11}{\left(x - 4\right) \left(x + 3\right)}\right)$$
=
$$\lim_{x \to 1^+}\left(\frac{x^{2} + 11}{\left(x - 4\right) \left(x + 3\right)}\right) = $$
$$\frac{1^{2} + 11}{\left(-4 + 1\right) \left(1 + 3\right)} = $$
= -1
Entonces la respuesta definitiva es:
$$\lim_{x \to 1^+}\left(\frac{x^{2} + 11}{- x + \left(x^{2} - 12\right)}\right) = -1$$