The latest demand equation for your Yoda vs. Alien T-shirts is given by
$$
q=-40 x+600
$$
where $q$ is the number of shirts you can sell in one week if you charge $$\$ x$$ per shirt. The Student Council charges you $$\$ 400$$ per week for use of their facilities, and the T-shirts cost you $$\$ 5$$ each. Find the weekly cost as a function of the unit price $x$. Hence, find the weekly profit as a function of $x$ and determine the unit price you should charge to obtain the largest possible weekly profit. What is the largest possible weekly profit?