[Basic Database - Relational Algebra] I'm really stuck on this. Many many thanks!

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https://docs.google.com/document/d/1hjyQAXKW9Y1bK7rjDNdy99RPwBzeXYOpYJY9sv-mU0s/edit?usp=sharing

Bob Parr, aka "Mr. Incredible", breaks large amounts of office equipment because of his super strength. His boss is starting to get annoyed and wants him to translate a series of questions to relational algebra so that they can order replacement equipment. The database they are using only speaks relational algebra. Bob skipped that day in his database course (because he was saving the world) and needs your help. Can you help Bob translate the relational algebra query to get him the information his boss needs? Product(maker, model, type) PC(model, speed, mm, harddrive, screen, price) Laptops(model, speed, ram, harddrive, screen, price) Printer(model, color, type, price) Find the make and model of all the PCs that are less than $1000 but greater than $800 dollars. What are the models of PCs that are not made by a company that also makes laptops? Using no aggregate function, list the maker that makes the PC with the fastest processor. Which maker makes at least 3 differently colored printers but does not make a PC with a 13-inch screen? What maker does not make a red printer or a laptop under $800? Which maker makes the most unique laptop models