①x÷70%= 3
②3.5 + 0.4x= 10.7
③x-x= 18
④x:0.4=5:1.8
2x﹣13=39 13x﹣7.5x=3.4
2x+2.7=24.7 x-x= =
40%x+25=45 x-15%x=17 2x+30%x=18.4
4x÷(1-65%)=80 120%x-x=0.8 49+40%x=89