LetP(x,y)=x+y=2andQ(x,y)=xy0. Decide whether each of the following propositionsis true or false. Justify your answer.

1.xN,yN,P(x,y).

2.xN,yN,P(x,y)x is different from y.

3.xN,yN,Q(x,y).

4.xZ,yZ,Q(x,y).