Hi everyone.. I'm new here and I dont know where to post.. So, these are questions about relational algebra which I would like to discus with all of you..

The following tables form part of a database held in a relational DBMS:

Hotel (hoteNo, hotelName, city)
Room (roomNo, hotelNo, type, price)
Booking (hotelNo, guestNo, dateForm, dateTo, roomNo)
Guest (guestNo, guestName, guestAddress)

These are pictures of the questions:
http://s12.postimage.org/fxi7n47qx/20130227_012025.jpg

http://s12.postimage.org/u5chpi9tl/20130227_012051.jpg