解:原式= 19.2=14.8-0.4x+0.6x = 19.2-14.8+0.4x=0.6x = 4.4+0.4x=0.6x = 4.4=0.6x-0.4x = x=22
-0.2x=14.8-19.2-0.2x=-4.4x=22