If point B has coordinates (−8, 1), what are the coordinates of the point when it is reflected across the y-axis?

Answer 1

A reflection across the y-axis is a horizontal shift the distance to the y axis and then that same number of units to the other side.

Since you are at -8 move it 8 units to the line of reflection and then 8 more units horizontally beyond the other side..

There is no vertical shift so your reflection becomes (8,1)