What if the slope of the graph

An architect is designing a water fountain for a park she uses the given function to model the water jet flowing from the fountain nozzles where h(x) gives the height of the water jugs in feet x feet from the starting point h(x)=-1/20x+x+15

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

Which expression gives you the distance between the points (5,1)and(9,-6)