This shows a set of axes with the scales marked from minus 3 to 3 on both the horizontal x-axis and the vertical y-axis. The axes intersect at the origin. Four points (A, B, C and D) are marked. A is opposite 3 on the x-axis and opposite 1 on the y-axis and is shown with the co-ordinates (3,1). B is opposite minus 3 on the x-axis and opposite 1 on the y-axis and is shown with the co-ordinates (-3,1). C is opposite minus 2 on the x-axis and opposite minus 2 on the y-axis and is shown with the co-ordinates (-2,-2). D is opposite 2 on the x-axis and opposite minus 1 on the y-axis and is shown with the co-ordinates (2,-1).