Rotation of points on a graph

[isu23pink]

"rotation of 90degress about the point (0,0)" for this graph
[attachment=0:1npuaelz]Untitled.jpg[/attachment:1npuaelz]

i thought i understood it because it was just a basic 90degress rotation of the points.
this is what i got:
P' <0,-3>
Q' <3,-5>
R' <2,-7>
S' <0,-8>

but my teacher said i was wrong....so what exactly is it suppose to be then?

 

[akoaysigod]

(A, B) rotated 90 degrees around the origin is (-B, A) ex, (17, 3) rotated 90 degrees would be (-3, 17). Apply that to your problem.