To detele facebook page you need to do this:
1. login into your facebook account in which you want to delete facebook page.
2. click "Adverts & Pages".
3. choose desired Page, which you want to delete and press "Edit Page"
4. on left side, choose "Manage Permission".
5. finally in delete section press "Permanently delete this Page"
6. in popup windows once again press "delete" to confirm that you want to delete it.