Nation A Y=225-X240 UA=XY12 Nation B Y=121-X2186 UB=XY12 Questions: Answer the following questions. Show full solution to get full points. In all questions, briefly annotate/describe the steps that you are doing and why you are doing it (see example at the last page) Does nation A's economy exhibit constant opportunity cost in production? How about nation B? Support your answer using numeric/quantitative example (5 points)