A line segment has endpoints (1,1) and (4, 4). demonstrating the properties of reflections across the y-axis, what are the reflected end points?

To find the reflected endpoints across the y-axis, we need to change the sign of the x-coordinates while keeping the y-coordinates the same.

The original endpoints are:

Endpoint A: (1, 1)
Endpoint B: (4, 4)

To reflect across the y-axis, we swap the signs of the x-coordinates:

Endpoint A': (-1, 1)
Endpoint B': (-4, 4)

Therefore, the reflected endpoints across the y-axis are:
Endpoint A': (-1, 1)
Endpoint B': (-4, 4)