When a point \((x, y)\) is reflected across the x-axis, the x-coordinate remains the same, while the y-coordinate changes sign.
For the point \((5, 10)\):
- The x-coordinate is 5 (which remains the same).
- The y-coordinate is 10 (which becomes -10).
Therefore, the coordinates of the reflected point are \((5, -10)\).
So the correct response is:
(5, −10)