To find asymptotes of the function we look at the graph where it get close to x and y
We have vertical at x and horizontal asymptotes at y
In the left part of the graph , the graph gets close to y=0 but it does not crosses y=0
So the horizontal asymptote at y=0
Also the graph goes on increasing till x=-1, the graph gets close to -1 but it does not cross x=-1
So the vertical asymptote at x=-1
In the middle part of the graph goes close to x=-1 and x=3
So the vertical asymptote at x=-1 and x=3
In the last part of the graph , the graph is close to x=3 and it does not cross x=3.
also the graph does not cross y=0
So the horizontal asymptote at y=0, the vertical asymptote at x=3
After combining all the asymptotes
x=-1, y=0, x=3