Consider the following premises. For all x_15, x_15 is an artist or x_15 is not a janitor. For all x_15, x_15 is a janitor. For all x_15, x_15 is an artist if and only if x_15 is a taxi driver. Can we infer the following from them? If we can, name the inference rule being used: For all x_15, x_15 is a taxi driver or x_15 will play a game.
 From the fact that for all x_15, x_15 is an artist if and only if x_15 is a taxi driver we can infer that for all x_15, if x_15 were an artist, then x_15 is a taxi driver via universal biconditional elimination. From the fact that for all x_15, x_15 is an artist or x_15 is not a janitor we can infer that for all x_15, if x_15 were a janitor, then x_15 is an artist via universal rewriting. From the fact that for all x_15, if x_15 were a janitor, then x_15 is an artist, and that for all x_15, x_15 is a janitor we can infer that for all x_15, x_15 is an artist via universal modus ponens. From the fact that for all x_15, if x_15 were an artist, then x_15 is a taxi driver, and that for all x_15, x_15 is an artist we can infer that for all x_15, x_15 is a taxi driver via universal modus ponens. Finally, from the fact that for all x_15, x_15 is a taxi driver we can infer that for all x_15, x_15 is a taxi driver or x_15 will play a game via universal addition. Therefore, the answer is yes.