Could you guys help me with balancing Chemical Equations?

Combustion in automobile engines takes place when fuel and oxygen are combined and ignited in the cylinders of the engine. However, the air that provides the oxygen for combustion also introduces nitrogen into the engine.The nitrogen reacts with oxygen at the high temperatures present in the engine, producing nitrogen oxide compounds, which are a major componet of smog. In one of these reactions, nitric oxide, NO, reacts with oxygen,O2,to form nitrogen dioxide,NO2. Write the balance equation for this reaction.