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.