What is the rule for a reflection across the x axis?

Question

*
(x,y) → (-x, y)
(x,y) → (-x, -y)
(x,y) → (x, -y)

Answer 1

The rule for a reflection across the x-axis is:

\((x, y) \rightarrow (x, -y)\)

This means that the x-coordinate remains the same while the y-coordinate is negated.