Might be kind of hard to explain but just try to explain as much as u can.

The rule for a rotation by 270 ° about the origin is (x,y) ⇒ (y,-x)
Rotating the triangle PQR to create an image of the triangle involves moving the triangle PQR in a circular direction.
The coordinates of the given triangle are:
Using the rule, the coordinates now are:
In the attatchment, the answer is in pictoral form.