how do you reflect a shape over the x or y axis when its already on the line, like the preimage is already on to of the line, how do you reflect it?
3 answers
if the original point is on the line of reflection, it just stays there.
but what if none of the points are on it, but the shape it makes is, like a triangle, two points on one side, another on the other.
just consider each point. The shape will remain unchanged, just flipped. Just cut out a triangle, and flip it over. Has anything actually changed?