Need help ASAP can you help me solved the problem ?

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Arestaurant charges $100 to rent its banquet room for an event. it also charges $15 to serve dinner to each guest. write an equation for the total cost of the banquet room in terms of the number of guests. deine your variables. what is the total cost of the banquet room for 20 guests?

If sin(x) = 0 and cos(x) = 1, what is tan(x)?