What is the result of reflecting (13,8) across the x-axis, and how do you get it

The result of reflecting the point (13,8) across the x-axis is (-13,8).

To get this result, you simply change the sign of the x-coordinate of the original point while keeping the y-coordinate the same. In this case, the x-coordinate of the original point (13) becomes -13 when reflected across the x-axis.