(1)效用最大时MUx/Px=MUy/Py2X+3Y=120所以Y/2=X/32X+3Y=120所以X=30Y=20(2)Px'=2×1.44=2.88(元)U=30×20=600所以MUx/Px=MUy/PyXY=600所以Y/2.88=X/3XY=600所以X=25Y=24所以△R=2×25+3×24-120=50+72-120=2(元)