Question

are there ways to know if there is a black hole present

Answer 1

Yes. You can tell if a black hole is present by the warp of light around it or the bending of gravity.

Answer 2

That's a nice theory. But honestly black holes are as real as dark matter

Answer 3

You heard Forsure, black holes don't exist. His empirical evidence has made it apparent.

Answer 4

For the record I'd take compassionate's answer to school. However there is absolutely nothing but equations and conjecture as evidence as to the existence of black holes.
Equations are fairly good "evidence". Despite that it is all a theory attempting to make sense of what we perceive from our little rock here.