Consider the following premises. Joseph is sad if and only if Michael is a writer. If Michael reads a book, then Joseph is sad. For all z_3, z_3 is a writer or z_3 will read a book. Can we infer the following from them? Joseph is sad.
 From the fact that for all z_3, z_3 is a writer or z_3 will read a book we can infer that Michael is a writer or Michael is reading a book. From the fact that Joseph is sad if and only if Michael is a writer we can infer that if Michael were a writer, then Joseph is sad. Finally, from the fact that if Michael were a writer, then Joseph is sad, that if Michael reads a book, then Joseph is sad, and that Michael is a writer or Michael is reading a book we can infer that Joseph is sad. Therefore, the answer is yes.