Please answer following in relational algebra using given

Question

Given a set of relations

Customer (custId, fname, lname, address, city, state, zip, phone)

Dealership (dealerId, dealerName, address, city, state, zip, phone)

SalesTeam (salesId, dealerId, fname, lname)

Inventory (VIN, dealerId, Make, Model, color, modelYear, invoice_price, net_cost, msrp)

Transactions (custId, salesId, VIN, date, salePrice)

Please answer following in Relational Algebra using given relations. Please list all possible combinations if apply

1. List all pairs of salesperson and vehicles which sale prices are below costs?
2. List all customers and their sales people whom bought three or more vehicles?
3. List all vehicles sold from dealerships locate in Riverside county since beginning of 2015?
4. Please find the top sale dealerships in past 2 years?
5. Find total number in stock at each dealership on Honda Civic?
6. Find net revenue for each dealership on sales in year 2016?
7. List all customers who bought cars outside their local dearships?