0.4x+3.5=6.3
x:4=16:5
0.54×50+2x=32 6.8﹣0.8x=2.8 4:x=:34
:x=:5 8x﹣5.1x=2.9 (0.4+x)×3=2.7
7x+3×16=69 8:x=4:0.8
⑴;⑵
12﹣5x=6.5
22.5:4=x:5
① ②
①1.5x-2.8=4.7
②
③12: =
①
③ =3:2