1.1) Let line L have homogeneous coordinates (1, 2, 1) and point P have homogeneous coordinates (-3, 1, 1]. Does point P lie on line L?

Yes or no.

1.2) Let line L have homogeneous coordinates [1, 2, 1) and point P have homogeneous coordinates [6, -3,1]. Does point P lie on line L?

Yes or no.

1.3) Let point P have homogeneous coordinates (a, b, 0] and line L have homogeneous coordinates [-2b, 2a, a+b]. Does point P lie on line L?

Yes or no