well, the Y will always take the positive (or absolute) value of x,
So:
x=2, y=1
x=1, y=1
x=0, y=0
x=-1, y=1
x=-2,y=2
If you plotted those points, Y would NEVER be negative, so the line would never drop below the X axis. Thus it would always be positive and not in Quadrant 3 or 4 :)