Factor the following statement: 4x2 + 8x

What is this equation in point-slope form?

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

Don't know how to find x given these segment lengths