3. (20) Consider the relation schemas faculty (SSN, last-name, first-name, street, city, state student - SSN, last-name, first-name, street, city, state) and the following instance: 67-9009 Bai 980-67-8765 Jackson Ma Baton Baton R Re 980-67-8765 Ro State Washington Baton Rouge LA (10) Is this instance a legal instance of relation faculty? Why? a. b. (10) Is this instance a legal instance of relation student? Why? 4. (15) I have a relational database schema: Professor (Professorld, name, Deptld, password, address) Student (Studentld, name, Deptid, year, address) CourseOfferings CrsCode Semester Course CrsCode, CrsTitle, CrsDescription) Teaches Professor ld. CrsCode, Semester) Write out the relational algebra for the following queries. 1) Find the semesters when course operating systems' was offered. 2) Find the names and Deptld of all professors who taught in spring 2010