Let [phi](u,v)=(3u+v,u-2v). Use the Jacobian to determine the area of [phi]R for: R=[2,5]X[1,7] 3. The attempt at a solution - I'm really not sure why I keep getting the wrong answer on this problem. the problem gives you two R's to solve for and I got the right answer for the first one (R=[0,3]X[0,5]), but I'm not getting the right answer for the 2nd R. I would think you would solve the problems the exact same way, but I'm not sure since I can't get the right answer. Would R being changed affect how you work the problem?