Math Help - Planes

1. Planes

A plane P passes trough the points (1,1,1) and (2,0,3)

And it is perpendicular to the plane Q

x+2y-3z=0

What is the equation for plane P?

$<1,-1,2>$ is the vector determined by the two points.
So the normal to the needed plane is cross product $<1,-1,2>\times <1,2,-3>$.