Consider the following premises. For all x_5, if x_5 plays tennis, then x_5 is a mechanic. For all x_5, if x_5 were a politician, then x_5 is playing tennis. For all x_5, x_5 is a musician. For all x_5, x_5 is a politician. Can we infer the following from them? There is at least one x_5 for which either x_5 is a musician or x_5 is a mechanic are not true.
 From the fact that for all x_5, if x_5 were a politician, then x_5 is playing tennis, and that for all x_5, if x_5 plays tennis, then x_5 is a mechanic we can infer that for all x_5, if x_5 were a politician, then x_5 is a mechanic. From the fact that for all x_5, if x_5 were a politician, then x_5 is a mechanic, and that for all x_5, x_5 is a politician we can infer that for all x_5, x_5 is a mechanic. Finally, from the fact that for all x_5, x_5 is a musician, and that for all x_5, x_5 is a mechanic we can infer that for all x_5, x_5 is a musician and x_5 is a mechanic, which contradicts that There is at least one x_5 for which either x_5 is a musician or x_5 is a mechanic are not true. Therefore, the answer is no.