Verified answer

3,5х-2,3х+3,8=4,28

1.2x=4.28-3.8

1.2x =0.48/1.2
x=0.4 

Verified answer

3,5х-2,3х+3,8=4,28

1,2х=4,28-3,8

1,2х= 0,48

х=0,48:1,2

х= 0,4

Проверка:

0,4*3,5-2,3*0,4+3,8=4,28

 4,28=4,28