Respuesta :
All it means is that a number equals itself, for example 5=5 (pretty obvious ik but it's that simple). Remember it by thinking that a number would look into the mirror and see itself in its reflection (kinda sounds like reflexive).
It means something relating to itself. Its like if you have a problem 5+3=8 using the reflexive property says that the same thing is 8=3+5.