Change the sign of the x-coordinate
Keep the y-coordinate the same
Use the rule: (x, y) -> (-x, y)
For a point on the y-axis, the point stays the same
For a graph, mirror every point across the y-axis
Change the sign of the x-coordinate
Keep the y-coordinate the same
Use the rule: (x, y) -> (-x, y)
For a point on the y-axis, the point stays the same
For a graph, mirror every point across the y-axis