Answer:
(x,y) <-> (x-8, y-8)
Explanation:
Take note of where each point is:
A -> (3,6)
B -> (2,1)
C -> (8,2)
A' -> (-5,-2)
B' -> (-6,-7)
C' -> (0,-6)
Since the figures are congruent to each other, all the points follow the same translation rules. For example, to get from A to A', the distance from 3 to -5 is 8 to the left, and the distance from 6 to -2 is also 8 but down. So the translation rule would be (x,y) <-> (x-8, y-8)