Answer:No charge
Explanation:
Cu3PO4 is an ionic compound which my definition has no charge (or a charge of 0). But if you are referring to the ions themselves that make up the compound, PO4 is a polyatomic ion so you can look up its charge in a polyatomic ion chart (it is 3-). Thus since there are 3 Cu's per PO4^3-, each Cu must have a charge of 1+.