So we are given the following to prove, only by proof by contradiction
$\forall x(Q(x)\to P(y)) \vDash \forall xQ(x)\to P(y)$
Now the first thing that comes to mind in predicate logic when i am on a dead end is to perform Tarski's theorem about truth and see what types of structures ,the given types are true. But when it comes to analyzing the first part: $\forall x(Q(x)\to P(y))$ i am not very sure if i can say which structures(we want to find structures as sets, for example:for every x that makes Q true, there is a y that makes P truth etc) Anyway i need help finding the types for structures these types need to be true so after that i can move forward and start the proof by contradiction.Thanks