Question

I am given a graph and asked to derive the function from it. The answer key says y=(-3x^2-5)/(x^2-25)- use wolfram to graph for your convenience. I got the asymptotes but the -5 constant I don't get where it came from. Someone explain to me how to get that -5 constant?(I tried plugging in another point but it doesn't work, and I am not allowed to use a graphing calculator).
kuai
x^2 -25 =0
(x -5)(x+5) =0