there some ambiguity with this question.
If by X u mean a halogen, then charge will vary. The same applies if it is an inorganic element... Insufficient data!!
given the ionic formula X2O What is the charge of X?
2 answers
I would think X is +1 whether X is a halogen or not. Since it is an ionic compound, it is more than likely that X is a group I element and not a halogen (Na2O, K2O, Li2O, etc.)