Consider the following premises. There is at least one x_9 for which x_9 is curious or x_9 will not write a letter. For all x_9, x_9 will go running if and only if x_9 is curious. Can we infer the following from them? If we can, name the inference rule being used: For all x_9, the fact that x_9 writes a letter does not imply that x_9 is running.
That contradicts the premises. Therefore the answer is no.