Which is the better buy: 3 shirts for $15 or 5 shirts for $20?

What aspects of lines have to be diffrent

Can you simplify 4/7? 24 points will be awarded!

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