Consider the following premises. For all x_11, x_11 will read a book or x_11 will not drink water. There is at least one x_11 for which if x_11 reads a book, then x_11 is writing a letter. For all x_11, x_11 will drink water if and only if x_11 will write a letter. Can we infer the following from them? If we can, name the inference rule being used: For all x_11, if is not true that x_11 will read a book if and only if x_11 will drink water.
That contradicts the premises. Therefore the answer is no.