Answer:
See Explanation
Step-by-step explanation:
The question has missing details. So, I'll solve using a general assumption.
Let one of the coordinates of the figure be

Let the scale factor be n
When dilated, the new figure is:


To return the image back to the original figure, the new scale factor mus be a reciprocal of the previous scale factor i.e. 
So:

Substitute n(x,y) for A';



Take for instance:

-- scale factor



To get A from A', using the analysis above

