Redox (red for reduction and ox for oxidation)
In a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the heat of the reaction<span>. This is, the net energy released or absorbed (change) during a chemical reaction is the sum of the potential energy of the products less the sum of the potential energy of the reactants.</span>
So first we need to know what the formulas are:
Methane: 
Oxygen: 
Carbon Dioxide: 
Water: 
So then we follow the equation as specified in the question. Note that it does not need to be balanced, as the question states it wants the unbalanced equation:
→ 
This is the preliminary, unbalanced equation with the correct chemical formulas.