Solution:
To find the image of the point (8, 4) after a reflection over the y-axis, you change the sign of the x-coordinate while keeping the y-coordinate the same. This is because reflecting over the y-axis mirrors the point to the opposite side of the y-axis horizontally, but does not change its vertical position.Therefore, the image of (8, 4) after a reflection over the y-axis is (-8, 4).