Answer:
when you flip a shape across the plane its making it to its opposite.
definition:
When you reflect a point across the x-axis, the x-coordinate remains the same, but the y-coordinate is transformed into its opposite
Example:
When you look in a mirror you know how it reflects a different way? its the same thing with this the shape will change the same just like your face in the mirror stays the same but it changes the way you look at it
