Consider the following premises. Michael is a mechanic if and only if Richard is driving a car. For all y, y is not happy. Richard is driving a car if and only if Linda is happy. Can we infer the following from them? Michael is not a mechanic.
 From the fact that for all y, y is not happy we can infer that Linda is not happy. From the fact that Richard is driving a car if and only if Linda is happy, and that Linda is not happy we can infer that Richard is not driving a car. Finally, from the fact that Michael is a mechanic if and only if Richard is driving a car, and that Richard is not driving a car we can infer that Michael is not a mechanic. Therefore, the answer is yes.