Quick Geometry Help

Two vertices of a parallelogram are A(2, 3) and B(8, 11), and the intersection of the diagonals is X(7, 6).
A. Find the coordinates of the other two vertices. Make sure to show all of your work in finding the answer, and make sure your answer is clearly stated.
B. EXPLAIN what you had to do to find the answer. Basically, you are walking me through the steps you performed (in words) AND telling me why you did these things.