Consider the following premises. For all x_7, x_7 is happy if and only if x_7 is a musician. For all x_7, if x_7 were happy, then x_7 is a musician. Can we infer the following from them? If Karen were a musician, then Karen is happy.
 From the fact that for all x_7, x_7 is happy if and only if x_7 is a musician we can infer that for all x_7, if x_7 were a musician, then x_7 is happy. From the fact that for all x_7, if x_7 were happy, then x_7 is a musician, and that for all x_7, if x_7 were a musician, then x_7 is happy we can infer that for all x_7, x_7 is happy if and only if x_7 is a musician. From the fact that for all x_7, x_7 is happy if and only if x_7 is a musician we can infer that Karen is happy if and only if Karen is a musician. Finally, from the fact that Karen is happy if and only if Karen is a musician we can infer that if Karen were a musician, then Karen is happy. Therefore, the answer is yes.