设此三个数X,Y,Z
X-Y=Y-Z
X+Y+Z=12
XYZ=48
则
2Y-Z=12-Y-Z
48/YZ=2Y-Z
则
Y=4
(Z-2)(Z-6)=0
则
Z1=2
Z2=6
则该数列为2,4,6或6,4,2