How can I find a point between point A and point B, that is exactly x studs away from point A?

I tried this, but I am having trouble with the mathy bits:

CFrame.new(Position1):Lerp(CFrame.new(Position2), (1/(Position1-Position2).Magnitude)*Distance).p

I am trying to position an object between point A and point B, where instead of the percentage of the distances, I am trying to position it based on a fixed distance from point A. If the distance between point A and B is less than the object should be apart, then B will be between A and the object.