When you reflect a point across an axis, either the x value or the y value flips signs.
When you reflect across the x axis, the sign of the y value changes(+ to -) or (- to +)
When you reflect across the y axis, the sign of the x value changes (+ to -) or (- to +)
The point reflected across the x-axis because the sign of the y value changed/flipped, while the sign of the x value stayed the same.
