Final answer:
To reflect the point (-7,-2) across the line y=9, maintain the same x-coordinate and add twice the distance from the original point to the line to the line's y-coordinate, resulting in the reflected point (-7,20).
Step-by-step explanation:
The question involves reflecting a point across a horizontal line in a coordinate plane.
To reflect the point (-7,-2) across the line y=9, we determine the distance of the point from the line of reflection (which is 11 units) and then translate the point that same distance on the opposite side of the line.
The reflected point will have the same x-coordinate as the original point, so the x-coordinate remains -7.
The y-coordinate will be the line's y-value plus the distance, so it will be 9 + 11, resulting in a new y-coordinate of 20.
Therefore, the reflected point is (-7,20).