What are the two verbs in in this page that are in pive voice?

The two verbs in pive voice are "is shown" and "is studied". The fist verb should not be changed because, well... it wouldn't sound right! It would have to be something like, 'A map of Konigsberg's bridges showed at the right'. There's no way to say that sentence without an 'are shown' or 'is shown'. The second verb could be changed or not, depending on what you wanted to get across. 'The map is studied by Mr. Euler carefully' or 'Mr. Euler studied the map carefully'. You would have to change the structure of the sentence.