Final answer:
Point C' is the reflection of point C over the x-axis. The coordinates of point C (6, 4) become (6, -4) for point C' after reflection.
Step-by-step explanation:
When point C is reflected over the x-axis, the x-coordinate remains the same, but the y-coordinate changes its sign. Point C is initially at coordinates (6, 4). After the reflection over the x-axis, the x-coordinate will stay 6, but the y-coordinate will become -4, since reflection over the x-axis inverts the sign of the y-coordinate. Therefore, the coordinates of point C' after the reflection will be (6, -4).