House A 6 320 Figure 1 Figure 2 Tessa has 80 ft of fencing available to construct a fence that will divide her garden into four rectangular sections Her house forms one side of the garden and ar represents the width as shown in Figure 1 a Express the total area of the four sections as a function of x A a b Find the domain of the function Write your answer as a compound inequality involving a Domain of A CE c Using the graph of A r shown in Figure 2 determine the dimensions that yield the maximum area