x+50%=42 :x=:0.8
x+40%x=2.1 =:15
5x﹣70%×13=8.9
1+75%x=2.8 x:3=
3.6x﹣20%x=102
7.2:x=
解:3.6x=57.6
3.6x÷3.6=57.6÷3.6
x=16