Step 1:
\The points on the plane are
and 
The points
are lies on the plane then their vectors
are lie on the same plane.
If
are the two points then the component form of vector
is

If
and
are the two points then the component form of vector
is

Consider
.

.
From geometric properties of the cross product,
is perpendicular to both
.
Then
is perpendicular to plane passing through the points
.
Solution :
\
is a non-zero vector perpendicular to plane passing through the points
.