Tomamos como el límite
$$\lim_{x \to 13^+}\left(\frac{- 11 x + \left(x^{2} + 12\right)}{x^{2} - 144}\right)$$
cambiamos
$$\lim_{x \to 13^+}\left(\frac{- 11 x + \left(x^{2} + 12\right)}{x^{2} - 144}\right)$$
=
$$\lim_{x \to 13^+}\left(\frac{x^{2} - 11 x + 12}{\left(x - 12\right) \left(x + 12\right)}\right)$$
=
$$\lim_{x \to 13^+}\left(\frac{x^{2} - 11 x + 12}{x^{2} - 144}\right) = $$
$$\frac{- 143 + 12 + 13^{2}}{-144 + 13^{2}} = $$
= 38/25
Entonces la respuesta definitiva es:
$$\lim_{x \to 13^+}\left(\frac{- 11 x + \left(x^{2} + 12\right)}{x^{2} - 144}\right) = \frac{38}{25}$$