We need to identify the points of the pre-image and image and compare them.
So, points of the pre-image are:
(-6, 8), (-3, 6), (-9,4), (-6,4), (-2,3) and (-3,0)
At the same way, point of the image are:
(-8, -6), (-6, -3), (-4, -9), (-4, -6), (-3, -2) and (0,-3)
Now we can see that if the pre-image point is (x,y) the image point is (-y, x)
Answer: the algebraic rule is that every point (x,y) is moved to point (-y, x)
For example, (-6,8) is moved to point (-8, -6).