Consider the following premises. For all x_10, x_10 is a musician. For all x_10, if x_10 were a musician, then x_10 is happy. Can we infer the following from them? If we can, name the inference rule being used: Jessica is happy or Sarah is a poet.
 From the fact that for all x_10, if x_10 were a musician, then x_10 is happy, and that for all x_10, x_10 is a musician we can infer that for all x_10, x_10 is happy via universal modus ponens. From the fact that for all x_10, x_10 is happy we can infer that Jessica is happy via universal instantiation. Finally, from the fact that Jessica is happy we can infer that Jessica is happy or Sarah is a poet via addition. Therefore, the answer is yes.