2. A simple connected graph G has ten vertices of degree 7 and one of degree 6, and no other vertices. (a) [3 marks]. How many edges does it have? Be

sure to state clearly any results that you use to get your answer. (b) [2 marks]. If this graph had a planar drawing, how many faces would it have? Be sure to state clearly any results that you use to get your answer. (c) [4 marks]. Explain why it follows that G cannot be planar.