Question 1046763
What transformation transforms (a, b) to (a, −b)
For example: Blue Point to Green Point
Using as Ex: (6,8) and (6,-8) (Green)
a reflection over the x-axis 
{{{drawing(300,300,    -10,10,-10,10, 
 grid(1),
circle(6, 8,0.4),
green(circle(6,-8,0.4)),
graph( 300, 300, -10,10,-10,10,0))}}}