Question

What is the image of the point (−7,−3) after a rotation of 9 0 ∘ counterclockwise about the origin?

Answer 1

It is best to use graph paper to visualise. A(-7, 9) is in 2nd quadrant, rotating 90 CCW brings the point in the 3rd quadrant to (-9, -7)

in general P (a, b) CCW P’(-b,a)