①8.4:0.35=x:1.5
②6.5:x=:75%
③(x+2):2=21:6
④:=
⑤1:5=1:x
⑥=
①1.2x-0.5x=3.5
②
③
①x+80%x=28 ②3x- 1.6=3.8 ③