Question

Reflect triangle ABC with respect to the x-axis and the y-axis. A(2,-1), B(6,-3), C(1,-3) What are the vertices of triangle A′B′C′?

Answer 1

Reflection across the x-axis: (x,y) -> (x,-y). Reflection across the y-axis: (x,y) -> (-x,y). Doing both (in either order) gives (x,y) -> (-x,-y).

So
- A(2,-1) -> A′(-2,1)
- B(6,-3) -> B′(-6,3)
- C(1,-3) -> C′(-1,3)