Le Chatelier's principle states that when a change is brought to a system in equilibrium, the equilibrium will shift in a manner to reverse that change.
If the pressure is increased, the system will try to reduce the pressure. The only way it can do this is by producing less gas. Therefore, shifting the equilibrium to the left. Thus, the statement is true.
CH2O. You can reduce 8, 16, and 8 to 1, 2, and 1. You just simplify the numbers. When there is no number after an element, it means that there is one of them.