Consider the following premises. For all x_5, if x_5 were a scientist, then x_5 is a taxi driver. For all x_5, x_5 will play a game. There is at least one x_5 for which x_5 is a scientist. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_5 for which x_5 is a scientist.
That is one of the premises. Therefore, the answer is yes.