Answer
$V.A.$ $x=1$,
$H.A$ $none$,
$O.A.$ $y=x+1$.
Work Step by Step
Given $f(x)=\frac{x^2+4}{x-1}=x+1+\frac{5}{x-1}$, we can identify the following:
vertical asymptote $V.A.$ $x=1$,
horizontal asymptote $H.A$ $none$,
oblique asymptote $O.A.$ $y=x+1$.
