How Do We Graph Rotations?

Rotation a transformation that turns on object around fixed point.
Example ;

90 degrees
(x,y) -> (-y,x)
180 degrees
(x,y) -> (-x,-y)
270 degrees
(x,y) -> (y,-x)

How do we solve problems using reflections?

you can reflect the y axis or either the x axis.
another way is by using diagonal lines.
but as a short cut you can just swap the y and x axis.

example : (x,-y) -> (-y,x)
(-x,y) -> (y,-x)