Translate the following inference to logic notation: For all x, if x_10 were a janitor, then x_10 is playing a game. David is an electrician or Linda is playing a game. For all x, if x_10 plays a game, then x_10 is a janitor. If David were an electrician, then Linda is a janitor. Therefore Linda is a janitor.
forall x: P(x) -> Q(x). p or Q(a). forall x: Q(x) -> P(x). p -> P(a). Therefore P(a).