In graph theory, an adjacency matrix A has an entry of 1 at if there is an edge connecting node i with node j, and a zero otherwise. (Such matrices come up in network analysis.) Suppose that a graph with five nodes has adjacency matrix

Let T : ? be given by T(x) = Ax. (a) Describe how to use T(x) to determine the number of edges connected to node j . (b) How can one use T(x) to help determine the total number of graph edges?

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