I honestly have no clue as to where to start with this question. My TA told us to think of it parts:
1) Consider what having a set unified with 'not P' means. 2) What this union being unsatisfiable would mean. 3) What this would mean for the relationship of 'if Q then P' with Gamma.
We barely touched this module yet so I don't know what to start off with. Any help would be greatly appreciated!