Identify the initial amount a and the growth factor b in the exponential function a(x)=30 * 8.3^x

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

Which graph represents the linear function below? y-4= (4/3)(x-2)

Rounded to the nearest tenth, what is the value of x