When a question asks you to give an example in the domain of real numbers where
$\forall x$, $\forall y$, $\exists z$ P(x, y, z) is true,
but $\forall x$, $\exists y$, $\forall z$ P(x, y, z) is false
How would I prove that my example will satisfy both these statements? Or what should I already know or apply in this question to prove it? Whenever I get a question prove the statement, I get a brain fart and don't what to write.