(2) O {0,0} A {3,1} B {4,3} C {1,2} D {4,3} is at point B.
OC// and =AB, so the quadrilateral OABC is a parallelogram.
(3) Starting from the origin, first translate to P according to the translation amount {2,3}, then to Q according to the translation amount {3,2}, and finally to O according to the translation amount {-5,5}.