When an object is reflected over the y-axis, what happens to its y-value?

When an object is reflected over the y-axis, its y-coordinate remains unchanged. This is due to the nature of reflection, where points on the coordinate plane flip over a specific axis. The y-axis acts as a mirror in this scenario.

For instance, if you take a point with coordinates (x, y), after reflecting it over the y-axis, the new coordinates will be (-x, y). Notice that while the x-coordinate changes sign, the y-coordinate stays exactly the same throughout this transformation. Therefore, reflecting an object over the y-axis has no effect on its y-value, which confirms that the correct answer is that it stays the same.