How do I show my work for 90-(5x5) x2

Tickets to a science exposition cost $5.75 each for studentd and $7.00 for adults.how many students and adults went if the ticket charge was $42.75

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?

In which direction does the left side of the graph of this function point? a(x) = 3x - x2 + 4x - 2