A line contains the points (6,−3) and (3, 1) . When this line is reflected across the y -axis, what are the two new points?

When a point is reflected across the y-axis, the x-coordinate becomes its opposite.

For the point (6, -3), the reflection would be (-6, -3).

For the point (3, 1), the reflection would be (-3, 1).

Therefore, the two new points after reflecting across the y-axis are (-6, -3) and (-3, 1).