When a point is reflected over the y-axis, which change occurs?

When a point is reflected over the y-axis, which change occurs?

• A. The x-coordinate changes sign and the y-coordinate remains the same
• B. The x-coordinate changes sign and the y-coordinate changes sign
• C. Both coordinates change sign
• D. The x-coordinate remains the same and the y-coordinate changes

Answer: (A)

Reflecting a point over the y-axis means mirroring it across the vertical line x = 0. The horizontal distance to the axis stays the same, but on the opposite side, so the x-coordinate changes sign while the y-coordinate stays the same. In other words, a point (x, y) maps to (-x, y). For example, (4, 7) becomes (-4, 7). If only the y-value changed, that would be a reflection over the x-axis; if both coordinates changed sign, that would be a reflection over the origin.

Reflecting a point over the y-axis means mirroring it across the vertical line x = 0. The horizontal distance to the axis stays the same, but on the opposite side, so the x-coordinate changes sign while the y-coordinate stays the same. In other words, a point (x, y) maps to (-x, y). For example, (4, 7) becomes (-4, 7). If only the y-value changed, that would be a reflection over the x-axis; if both coordinates changed sign, that would be a reflection over the origin.