We know that the reflection of the point (x,y) across the y-axis is the point (-x,y). In this case, we have:
[tex]\begin{gathered} (x,y)=(-8,1) \\ \Rightarrow(-x,y)=(-(-8),1)=(8,1) \end{gathered}[/tex]
Therefore, the reflection across the y-axis of the point (-8,1) is the point (8,1).
