How do I balance the following chemical equation?

Question

____CH₄ + ___ O₂ → ___ CO₂ + ___ H₂O + ___ C + ___ CO

Answer 1

It's best the save the oxygens until the end so we can start with either carbon or hydrogen. Let's start with carbon.

There are 3 "C's" on the right so for our first attempt to balance, let's but a "3" as the prefix in front of CH₄:

3CH₄ + O₂ → CO₂ + H₂O + C + CO

Now we have 12 hydrogens on the left, so for our 2nd attempt to balance, lets put a "6" prefix in front of H₂O:

3CH₄ + O₂ → CO₂ + 6H₂O + C + CO

We now have balanced the "C's" and "H's" however, in looking at the oxygens, there is an odd number on the right and an even number on the right, To make the right an even number, lets add a "2" prefix in front of CO:

3CH₄ + O₂ → CO₂ + 6H₂O + C + 2CO

We now have messed up both the carbons and hydrogens so we can adjust their prefixes:

4CH₄ + O₂ → CO₂ + 8H₂O + C + 2CO

Now we see that there are 12 "O's" on the right and 2 on the left. We can fix this by adding a "6" prefix in front of the O₂:

4CH₄ + 6O₂ → CO₂ + 8H₂O + C + 2CO

Now everything is balanced.