We can find the horizontal asymptote of this kind of functions using the limit:
[tex]\begin{gathered} \lim _{x\to\infty}\frac{1}{x+5}-4=\frac{1}{\infty}-4=-4 \\ \lim _{x\to\infty}\frac{1}{x+5}-4=\frac{1}{-\infty}-4=-4 \end{gathered}[/tex]Therefore the equation of the horizontal asymptote is:
[tex]y=-4[/tex]
