The question is to determine whether the statement below is a valid translation of a English sentence, based on meaning of I(z, x), N(x) and *. I am not sure if using different quantifiers for the same variable is "legal", but when the sets C and F are disjoint surely it isn't even a well formed statement?
(∀x ∈ F) (∃x ∈ C) (∀z ∈ M) [I(z, x) ∧ N(z) =⇒ N(z ∗ x)]
Apologies if this is a stupid question, I have had no introduction to formal logic before, so I don't know what constitutes "legal" statements beyond intuition (which is dangerous to rely on).