The point (-3, 6) is reflected across the x-axis. What are the coordinates of its image?

Erklärung

A reflection across the x-axis keeps every point the same distance to the left or right and carries it the same distance to the other side of that axis, so the x-coordinate is untouched and only the y-coordinate changes sign. Negating the x-coordinate instead describes a reflection across the y-axis, which moves the point the wrong way.