Q1 FOR Z IS ????
Q3 FOR Z IS ???
You will need to post the questions if you expect someone to help you answer them...
Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
Welcome to the forum. Why hate it? It is a beautiful field.
In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.