Which transformation represents a reflection over the x-axis?

Question

Which transformation represents a reflection over the x-axis?

1. (x, y) → (−x, y) 
2. (x, y) → (x , −y) 
3. (x, y) → (y, x) 
4. (x, y) → (−y, x)

Answer 1

2 is the correct answer. When you reflect over the x-axis, the y value changes signs.