How would I work out these two problems, any formulas I need to know?

G M Finish update T-Shirt Profit Two fraternities, Sig Ep and Ep Sig, plan to raise money jointly to benefit homeless people on Long Island. They will sell Yoda vs. Alien T-shirts in the student center, but are not sure how much to charge. Sig Ep treasurer Augustus recalls that they once sold 80 shirts in a week at $7 per shirt, but Ep Sig treasurer Julius has solid research indicating that it is possible to sell 400 per week at $3 per shirt. (a) On the basis of this information, construct a linear demand equation for Yoda vs. Alien T-shirts. Hence obtain the weekly revenue R as a function of the unit price x. R(x) = (b) The university administration charges the fraternities a weekly fee of $100 for use of the student center. Write down the weekly profit P as a function of the unit price x. P(x) = Determine how much the fraternities should charge (in dollars per T-shirt) to obtain the largest possible weekly profit. x = $ per T-shirt What is the largest possible weekly profit (in dollars)? Show My Work (Optional)? Submit Answer 14. [-/1.08 Points] DETAILS WANEFMAC8 2.1.039. Website Profit The latest demand equation for your gaming website, www.mudbeast.net, is given by q=-200x + 1100 where q is the number of users who log on per month and x is the log-on fee you charge. Your Internet provider bills you as follows. Site maintenance fee: $30 per month High-volume access fee: $0.50 per log-on Find the monthly cost as a function of the log-on fee x. C(x) = Find the monthly profit as a function of x. P(x) = MY NOTES ASK YOUR TEACHER it.