Question

What is the image of the point (1,5) after a rotation of 180 counterclockwise about the origin?

Answer 1

We have the point (1,5)=(x1,y1)

In order to find the coordinate of the point after a rotation of 180°, we use the next equation

(x2,y2)=(-x1,-y1)

then the new point is

(x2,y2)=(-1,-5)