Reflecting over the Y Axis

Use the line segment tool to connect these point. You will create the points while creating line segments.
(-2, 1)
(-5, 5)
(-7. 2)
and back to (-2, 1).
Click the selection tool outside of the triangle to assure that no points or segments are selected.
Using the selection tool click each point on the triangle separately.
Display ----- Label Points
Mark the Y Axis for the reflection by double clicking or choose the Y Axis
Transform ----- Mark Mirror
Use the selection tool to highlight the triangle.
Transform ------ Reflect
Use the selection tool to deselect the reflected triangle.
Using the selection tool click each point on the relected triangle separately.
Display ----- Show Labels
What happens to the X coordinate, when we reflect in the Y Axis?
Please comment.
Use the selection tool to choose each point on the original and the reflected triangle.
Measure ----- Coordinates
What do you now notice about the x coordinate of the original and the reflected triangle?