To find the coordinates of vertex \( X' \) after reflecting vertex \( X(-3, 8) \) over the line \( y = 1 \), we first need to calculate the distance from the vertex \( X \) to the line of reflection.
- The line of reflection is \( y = 1 \).
- The y-coordinate of point \( X \) is \( 8 \).
- The distance from \( X \) to the line \( y = 1 \) is: \[ 8 - 1 = 7 \]
- To find the reflected point \( X' \), we move the same distance downward from the line of reflection: \[ 1 - 7 = -6 \]
So, the coordinates of vertex \( X' \) after the reflection are \( (-3, -6) \).
The answer is: (−3, −6)