①x+31=52
②0.8x=6.4
③10x÷4= 50
④3x-7.1=4.9
⑤4x+5x=18
⑥6.3×x- 2.8x=14
①20+x=35 ②3x+6x=81 ③8x-24=80
2x+5.4=18.9 2x-2.8=9.96 (x-0.8)×4=7.2
2x+5=17 3(x-2)=12
① ② ③
⑴6x-9=33 ⑵y+3y=28.4