x=0.4 （X-1）/0.3-(X-2)/0.5=1.20.5(X-1)/0.15-0.3(X-2)/0.15=1.20.5(X-1)-0.3(X-2)=0.180.5X-0.5-0.3X+0.6=0.18(0.5-0.3)X=0.080.2X=0.08X=0.4
