9. [4 marks] Use the change of variables x= u + 2v, y = 3u + 2 v in order to evaluate 3x - ydA, where R is the parallelogram in the xy-plane defined by the corner points R (0, 4) , (2, 10), (8, 12), and (10, 18). Hint: find 4 line equations in order to obtain the iterated integral with respect to the new variables