Consider the following premises. For all x_7, x_7 is fast or x_7 will not take a plane. For all x_7, x_7 will take a plane or x_7 is not fast. There is at least one x_7 for which x_7 will not take a plane. Can we infer the following from them? There is at least one x_7 for which x_7 is not fast.
 From the fact that for all x_7, x_7 will take a plane or x_7 is not fast we can infer that for all x_7, if x_7 were fast, then x_7 is taking a plane. From the fact that for all x_7, x_7 is fast or x_7 will not take a plane we can infer that for all x_7, if x_7 takes a plane, then x_7 is fast. From the fact that for all x_7, if x_7 were fast, then x_7 is taking a plane, and that for all x_7, if x_7 takes a plane, then x_7 is fast we can infer that for all x_7, x_7 is fast if and only if x_7 will take a plane. Finally, from the fact that for all x_7, x_7 is fast if and only if x_7 will take a plane, and that there is at least one x_7 for which x_7 will not take a plane we can infer that there is at least one x_7 for which x_7 is not fast. Therefore, the answer is yes.