Consider the following premises. For all x_4, x_4 will drive a car if and only if x_4 is a musician. For all x_4, x_4 will not climb a mountain. For all x_4, x_4 will drive a car if and only if x_4 will climb a mountain. Can we infer the following from them? For all x_4, x_4 is not a musician.
 From the fact that for all x_4, x_4 will drive a car if and only if x_4 will climb a mountain, and that for all x_4, x_4 will not climb a mountain we can infer that for all x_4, x_4 will not drive a car. Finally, from the fact that for all x_4, x_4 will drive a car if and only if x_4 is a musician, and that for all x_4, x_4 will not drive a car we can infer that for all x_4, x_4 is not a musician. Therefore, the answer is yes.