Given the following relations, write the Relational Algebra statements that will perform the queries listed below.

Student( snum: integer, sname: string, major: string, level: string; age: integer)

Class(name: string, meets_at: time, room: string, fid: integer) Enrolled(snum: integer, cname: string)

Faculty(fid: integer, fname: string, deptid: integer

Find the names of students not enrolled in any class Find the names of faculty who have only taught classes in room R128. Find the names of the students who are either History majors or are in a class taught by I. Teach.