1) (4, -2) + ( 2, 5) = (6,3)
2) (-3, 1) + ( 4,-7) = (1,-6)
3) (0, -4) + (-6, 7) = (-6,3)
4) (3, -3) + (-3,-3) = (0,-6)
5) (5, 4) + ( 1,-4) = (6,0)
6) (-5,-3) + ( 5, 3) = (0,0)