## Complex Analysis-Analytic Continuation

A function f is analytic in the whole complex plane beside 4 poles.
We know that -1,2,1+5i are poles of f and that f gets only real values in (-1,2).

Find the fourth pole of f and show that f is a real-valued function for every real z which isn't a pole.

I've tried using the symmetry principle but without any success..

Help is needed

Thanks !