You are the one who is "blabla"ing. You seem to have misread the question. The original question was about graphing , the set of points (x, y) such that xy is either negative or zero. Yes, |xy| is never negative but it is 0. The graph is the two axes- the x- axis on which y= 0 so |xy|= |x(0)|= 0 and the y-axis on which x= 0 so |xy|= |(0)y|= 0.
Yes, |xy| is never negative but it is 0.......which implies x=0 and y=0..................I agree.....
do not use the < 0 it is wrong............................................. ......
and be more polite......after all we just exchange here views and ideas....and if we disagree in some issues this is just another expression of the plurality of Mathematics...