The function \( f(x)=\dfrac{x}{x^{2}-6x-16}, \ x\in \mathbb{R}-\{-2,8\}. \)
decreases in \( (-\infty,-2)\cup(-2,8)\cup(8,\infty) \)
increases in \( (-\infty,-2)\cup(-2,8)\cup(8,\infty) \)
decreases in \( (-\infty,-2) \) and increases in \( (8,\infty) \)
decreases in \( (-2,8) \) and increases in \( (-\infty,-2)\cup(8,\infty) \)