A student is asked to balance an equation by using the half - reaction method. He determines the two half reactions as shown below. What should he write as the final, balanced equation?

In order to make the complete reaction equation out of the half equations, the students must combine the equations via addition of the equations. Next, after the half-reaction equations have been added, we eliminate the terms that occur on both sides. 
After the equations have been combined, and the like terms eliminated, we are left with the final reaction equation.