true or false any three points are contained in exactly one plane?

Answer 1

False. If they were in a line, they would be in infinite planes.

Answer 2

Almost true.

Any three points NOT ALL ON THE SAME LINE are contained in exactly one plane.

In the special case where all three points lie on the same line, then they are contained in an infinite number of planes - any of the ones that intersect that same line.

If the question was worded precisely the way you gave, then the answer is FALSE - because it isn't "any three" and "exactly one"

Answer 3

true