Consider the following premises. For all x_7, x_7 will go running if and only if x_7 is an electrician. For all x_7, x_7 will go running and x_7 is sad. Can we infer the following from them? There is at least one x_7 for which x_7 is not an electrician.
 From the fact that for all x_7, x_7 will go running if and only if x_7 is an electrician we can infer that for all x_7, if x_7 goes running, then x_7 is an electrician. From the fact that for all x_7, x_7 will go running and x_7 is sad we can infer that for all x_7, x_7 will go running. Finally, from the fact that for all x_7, if x_7 goes running, then x_7 is an electrician, and that for all x_7, x_7 will go running we can infer that for all x_7, x_7 is an electrician, which contradicts that There is at least one x_7 for which x_7 is not an electrician. Therefore, the answer is no.