1. Find the chromatic number of the following graphs and give the colour classes (colour class is the set of vertices with the same colour) D B 6 5 3 G H 2. Use the formula Pc(k) = Pc-(k)-PG/e(k) to find the chromatic polynomial of the following graph (take e as shown). 3. Find the chromatic index of the following graphs and give the colour classes (colour class is the set of edges with the same colour) E G B 6 5 H 1 2 3