Consider the following premises. For all x_14, x_14 is fast. For all x_14, if x_14 were sad, then x_14 is driving a car. There is at least one x_14 for which x_14 is sad if and only if x_14 is fast. Can we infer the following from them? For all x_14, x_14 will not drive a car.
 From the fact that there is at least one x_14 for which x_14 is sad if and only if x_14 is fast we can infer that there is at least one x_14 for which if x_14 were fast, then x_14 is sad. From the fact that there is at least one x_14 for which if x_14 were fast, then x_14 is sad, and that for all x_14, x_14 is fast we can infer that there is at least one x_14 for which x_14 is sad. Finally, from the fact that for all x_14, if x_14 were sad, then x_14 is driving a car, and that there is at least one x_14 for which x_14 is sad we can infer that there is at least one x_14 for which x_14 will drive a car, which contradicts that For all x_14, x_14 will not drive a car. Therefore, the answer is no.