Đáp án `+` Giải thích các bước giải:

 `1``.` 

`a)`
`(` `x` `+` `2,8` `)` `:` `5` `=` `0,3`
`x` `+` `2,8` `=` `0,3` `×` `5`
`x` `+` `2,8` `=` `1,5`
`x` `=` `1,5` `-` `2,8`
`x` `=` `-1,3`

`b)`

( `x` `+` `5/6` ) `×` `2` `×` `2/5` `-` `1` `×` `1/4` `=` `35%`

( x + `5/6` ) × `12/5` - `5/4` = `7/20`

( x + `5/6` ) × `12/5` = `7/20` + `5/4`

( x + `5/6` ) × `12/5` = `7/20` + `25/20`

( x + `5/6` ) × `12/5` = `32/20` = `8/5`

x + `5/6` = ( `8/5` ) : ( `12/5` )

x + `5/6` = ( `8/5` ) × ( `5/12` )

x + `5/6` = `8/12` = `2/3`

x = `2/3` - `5/6`

x = `4/6` - `5/6`

x = `-1/6`

Vậy x = -1/6

`c)`
( 1 - 2x ) : 2 = -1,5 : 3
1 - 2x = ( -1,5 : 3 ) × 2
1 - 2x = -0,5 × 2
1 - 2x = -1
-2x = -1 - 1
-2x = -2
x = -2 : -2
x = 1

d) 

`d)`
1,4x - x = -8,844
( 1,4 - 1 ) × x = -8,844
0,4x = -8,844
x = -8,844 : 0,4
x = -22,11

`e)`
2 × ( 1/2 x - 1/3 ) - 3/2 = 1/4
2 × ( 1/2 x - 1/3 ) = 1/4 + 3/2
2 × ( 1/2 x - 1/3 ) = 1/4 + 6/4
2 × ( 1/2 x - 1/3 ) = 7/4
( 1/2 x - 1/3 ) = 7/4 : 2
( 1/2 x - 1/3 ) = 7/8
1/2 x = 7/8 + 1/3
1/2 x = ( 21/24 ) + ( 8/24 )
1/2 x = 29/24
x = ( 29/24 ) × 2
x = 29/12