Please help:

Create the following relation that results from applying a DIFFERENCE relational operator to the tables Hotel and Room

The following tables form part of a database held in a relational DBMS:- HOTEL ROOM (HOTELNO, HOTELNAME, CITY) (ROOMNO, HOTELNO, RTYPE, PRICE) Hotel Room HOTELNO HOTELNAME CITY ROOMNO HOTELNO RTYPE PRICE 501 fb81 Grosvenor 19 London fb81 single 681 fb81 double 29 fb82 watergate Paris 701 fb81 family 39 chei Omni Shoreham London 1281 fb82 single 58 chez Phoenix Park London 1101 fb82 double 86 dce1 Latham Berlin 1881 ch81 single 29.99 Formulate the additional queries in relational algebra