Please show work so that I may take the math and apply it to other questions of this type.

Consider the system SO3(g)SO2(g)+21O2(g) For how many of the following equilibrium disturbances will the forward reaction be favored? (a) adding oxygen gas (b) applying more pressure to the system (c) removing sulfur dioxide as it is formed (d) adding argon gas Which one(s)? List in alphabetical order with spaces between letters