Consider the following premises. For all x_22, x_22 will work. For all z, z is a mechanic. For all z, z is a bartender. Can we infer the following from them? If we can, name the inference rule being used: Richard is a mechanic and David is working.
 From the fact that for all z, z is a mechanic, and that for all z, z is a bartender we can infer that for all z, z is a mechanic and z is a bartender via universal conjunction. From the fact that for all x_22, x_22 will work we can infer that David is working via universal instantiation. From the fact that for all z, z is a mechanic and z is a bartender we can infer that for all z, z is a mechanic via universal simplification. From the fact that for all z, z is a mechanic we can infer that Richard is a mechanic via universal instantiation. Finally, from the fact that Richard is a mechanic, and that David is working we can infer that Richard is a mechanic and David is working via conjunction. Therefore, the answer is yes.