Given C(2,9) under which reflection is C'(-2,9)

The correct answer is: Reflection over the y-axis.<br /><br />Explanation: When a point is reflected over the y-axis, the x-coordinate changes sign while the y-coordinate remains the same. In this case, the point C(2,9) is reflected to C'(-2,9), which means the x-coordinate has changed sign from 2 to -2, while the y-coordinate remains the same. Therefore, the reflection is over the y-axis.