Pick true or false for each question.

More definitions, are in the Ask Questions Here discussion. Two definitions you may need are:

Satisfiable $$ there is SOME interpretation that makes the wff true.

Unsatisfiable $-$ there is NO interpretation that makes the wff true.

If a predicate wff is valid then it is also satisfiable.

If a predicate wff is satisfiable then it is also valid.

The wff $($x$)($P$($x$)($y$)$ P$($y$))$ is valid.

If a predicate wff is invalid, then it can not be true in all possible interpretations.