complex number Argand plane Please provide me some hits how to solve below problem. > ABCD is a parallelogram on the Argand plane. The affixes of $A,B,C$ are $8+5i,-7-5i,-5+5i$, respectively .Find the affix of D.

Try to locate the 3 points on the plane and use the fact that a parallelogram has 2 pairs of equal and parallel sides to determine the 4th.