Show that the points `A(,1,2,3),B(-1,-2,-1),C(2,3,2) and D(4,7,6)` are the vertices of a parallelogram ABCD but it is not a rectangle.

Show that the points A(1,2,3),B(-1,-2,-1),C(2,3,2) and D(4,7,6) are the vertices of a parallelogram ABCD but not a rectangle.

Show that the points A(1,2,3),\ B(-1,-2,-1),\ C(2,3,2)a n d\ D(4,7,6) are the vertices of a parallelogram ABCD but not a rectangle.

Show that the points A(1,2,3),B(-1,-2,-1)C(2,3,2),D(4,7,6) are the vertices of a parallelogram.

Show that the points A(1, 2, 3,), B (-1, -2. -1), C(2, 3, 2) and D(4, 7, 6) are the vertices of parallelogram ABCD but it is not a rectangle.

Show that the points (1, 2, 3), (-1, -2, -1), (2, 3, 2) and (4, 7, 6) are the vertices of a parallelogram.

Show that the points (1, 2, 3), (-1, -2, -1), (2, 3, 2) and (4, 7, 6) are the vertices of a parallelogram.

Show that the points (1, 2, 3), (-1, -2, -1), (2, 3, 2) and (4, 7, 6) are the vertices of a parallelogram.

Show that the points (1, 2, 3), (-1, -2, -1), (2, 3, 2) and (4, 7, 6) are the vertices of a parallelogram.

Show that the points (3,-1,-1),(5,-4,0) ,(2,3,-2) and (0,6,-3) are the vertices of a parallelogram

Show that the points A(3, 1), B(0, -2), C(1, 1) and D(4, 4) are the vertices of a parallelogram ABCD.