In each of the following cases determine if the given set of points all lie on the same line.

- , , .
- , , .
- , , .

- The points are not on the same line since the unique line containing is given by
But, cannot be on this line since for any , the third coordinate of every point on the line will be 1, while the third coordinate of is .

- The points are not on the same line since the unique line containing the points is given by
But, is not on this line since if then we must have . However, with we have .

- The points are not on the same line since the unique line containing the points is given by
But then is not on this line since if then , but then . Hence, is not on the line.