How would I solve this using the 30-60-90 triangle

If i have 20$ and i gave 5$ away how much i got

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?

Identify one charcteristic of exponential growth