The co-ordinates of a point A are (2, -3, 6). Write down the co-ordinates of seven points whose absolute values are the same as those of the co-ordinates of the given point.
The given point is A (2, -3, 6) and has y-co-ordinate negative.
∴ The seven other points are:
(i) B for which all x, y, z are positive
∴ B is (2, 3, 6)
(ii) C for which x is negative, y and z are positive.
∴ C is (-2, 3, 6)
(iii) D for which x, y are positive and z is negative.
∴ D is (2, 3, -6)
(iv) E for which x, y are negative and z is positive.
∴ E is (-2, -3, 6)
(v) F for which x, z are negative and y is positive.
∴ F is (-2, 3, -6)
(vi) G for which x is positive and y, z are negative.
∴ G is (2, -3, -6)
(vii) H for which x, y, z are all negative.
∴ H is (-2, -3, -6)