The signs of a point's coordinates affect where the point is on a coordinate plane because an X-coordinate being negative or positive tells how far to the right or left of the Y-axis a point is. Vice versa, the Y-coordinate being positive or negative says how far above or below the X-axis a point is on a coordinate plane.
Each point will plot to only one place in the coordinate plane. So, I don't know what you mean by plotting anywhere and you'll get the same result. You won't
The answer would probably be 18 degrees below normal because the absolute values of the rest are 8 not 18 which is the absolute value of 18 degrees below normal.
650 kgs is equal to 1,433 lbs. I believe the mistake would be that they forgot to add a period in between 65 and the 0, because 65.0 kgs is equal to 143.3 lbs.