It can't be done. Without knowing the value of you won't be able to sketch it.
I don't see how that has anything to do with the question you first posted! However, here is a good way to find asymptotes for a hyperbola (which that clearly is). If x and y are both very, very large numbers then so are and so that, in comparison, we can ignore "1". That is, for very, very large x and y, the graph is almost identical with the two straight lines given by .
Now, how about telling us what the problem really is?