mieszkańcami

In a sentence

• Rozmawialiśmy z mieszkańcami miasta o ich problemach.

  We talked with the residents of the city about their problems.

  In this sentence, "mieszkańcami" is used in the instrumental case to indicate the group of people ('residents') with whom an action ('talking') was performed.

• Spotkanie z mieszkańcami wsi odbędzie się w sobotę.

  The meeting with the villagers will take place on Saturday.

  Here, "mieszkańcami" is also in the instrumental case, showing the association between the entity ('villagers') and the event ('meeting').

• Jakie są relacje pomiędzy mieszkańcami różnych dzielnic?

  What are the relations between the residents of different districts?

  In this case, "mieszkańcami" is again in the instrumental case, used to represent the parties involved in a relationship ('residents of different districts').