Determine the range of the graph

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

What is the quadric regression equation that fits these data

What is sin 7x/4 ? i need on this urgent trig