50=0.6x-0.4x=0.2xx=50/0.2=250
先移项,将0.4x移到等号右边,变成负的,即50=0.6x-0.4x0.2x=50解得x=250
50+0.4x=0.6x50=0.6x-0.4x50=0.2xx=50/0.2x=250
50+0.4x=0.6x 50=0.2x 50=0.2x 0.2x=50 x=50/0.2 x=250