Consider the following premises. For all x_9, x_9 is a taxi driver if and only if x_9 will work. For all x_9, if x_9 were happy, then x_9 is a taxi driver. There is at least one x_9 for which x_9 will not work. For all x_9, if x_9 were a taxi driver, then x_9 is happy. Can we infer the following from them? There is at least one x_9 for which x_9 is not happy.
 From the fact that for all x_9, if x_9 were a taxi driver, then x_9 is happy, and that for all x_9, if x_9 were happy, then x_9 is a taxi driver we can infer that for all x_9, x_9 is a taxi driver if and only if x_9 is happy. From the fact that for all x_9, x_9 is a taxi driver if and only if x_9 will work, and that there is at least one x_9 for which x_9 will not work we can infer that there is at least one x_9 for which x_9 is not a taxi driver. Finally, from the fact that for all x_9, x_9 is a taxi driver if and only if x_9 is happy, and that there is at least one x_9 for which x_9 is not a taxi driver we can infer that there is at least one x_9 for which x_9 is not happy. Therefore, the answer is yes.