infinite
Only one if they are non-collinear. An infinite number if they are collinear.
I have a feeling that I'm wrong but i guess that 2 planes can pass through 2 points
Nonee !
Infinitely many planes.
There are an infinite number of planes that pass through a pair of points. Select any plane that passes through both the points and then rotate it along the line joining the two points.
Only one.
three
three
One.exactly one
Exactly one.
just one
Infinitely many if the 3 distinct points are collinear. Otherwise just 1.