Triangle PQR was transformed by a reflection over the y-axis. Which of the following describes the effect of this transformation on the coordinates of each vertex?

• A. Both the x- and y-coordinates of each vertex are multiplied by $-1$.
• B. The x-coordinate of each vertex is multiplied by $-1$, while the y-coordinate remains the same.
• C. The x- and y-coordinates of each vertex are switched.
• D. The y-coordinate of each vertex is multiplied by $-1$, while the x-coordinate remains the same.

Answer: (B)

Verified step by step guidance

1. Recall that a reflection over the y-axis changes the position of points by flipping them across the vertical y-axis line.
2. Understand that the y-axis is the line x = 0, so reflecting a point across this axis affects the x-coordinate but not the y-coordinate.
3. Express the original coordinates of a vertex as \((x, y)\).
4. Apply the reflection over the y-axis transformation, which changes the x-coordinate to its opposite, resulting in new coordinates \((-x, y)\).
5. Conclude that the x-coordinate is multiplied by \(-1\), while the y-coordinate remains unchanged.