Answer:
The coordinates of C and D are (1, 3) and (-5, 1), respectivelly.
Explanation:
Since E is the midpoint of diagonals AD and BC (see attachment). That is:


The vectorial distances of AE and BE are, respectively:








Now, the relative vectorial distances to C and D are now obtained:






Lastly, the coordinates are found by the following vectorial equations:








The coordinates of C and D are (1, 3) and (-5, 1), respectivelly.