Question

Marissa wants to write an abbreviated set of directions for finding coordinates of a figure reflected across the y-axis. Which mapping notation is correct?
(x, y) right-arrow (negative x, y)
(x, y) right-arrow (x, negative y)
(x, y) right-arrow (negative x, negative y)
(x, y) right-arrow (y, x)

Answer 1

(x, y) → (−x, y)

Reason: reflecting across the y-axis flips the x-coordinate sign but leaves the y-coordinate unchanged. (The others are reflection across the x-axis (x,−y), the origin (−x,−y), and across y=x (y,x).)