(1)x+60%x=48, 1.6x=48, 1.6x÷1.6=48÷1.6, x=30; (2)x-
x=100; (3)x-25%x-25%x×80%=110, x-25%x-0.2x=110, 0.55x=110, 0.55x÷0.55=110÷0.55, x=200; (4)60%x+50%(400-x)=400×55%, 60%x+200-50%x=220, 0.1x+200=220, 0.1x+200-200=220-200, 0.1x=20, 0.1x÷0.1=20÷0.1 x=200. |