No, i had no idea there is an asymptote at x=0, so i tried graphing it from x=-10 to x=-1 (to avoid the asymptote if thats whats causing the problem with mathematica), but it still doesnt work. I found the explanation of the error, it says "Error messages are generated in this example because the symbolic parameters in the function to be plotted do not have numerical values."

So there can not be numerical values for the graph, i dont know how to get around that. I dont have a graphics calculator and im a scientist (chemist) maybe thats why im so bad at these questions...