To find the reflection of point P = (2, 6) across the y-axis, we need to change the sign of the x-coordinate while keeping the y-coordinate the same.
When reflecting a point across the y-axis, the x-coordinate becomes its opposite. Therefore, the reflected point R_y-axis (P) will have the coordinates (-2, 6).
So, R_y-axis (P) = (-2, 6).