bài 1)
a) 12 + 6 . ( -4) + |-26|
= 12 + (-24) + 26
= -12 + 26
= 14
b) ( 0,5 - `1/4` ) : `3/2` - `5/12` : `10/3`
= ( `1/2` - `1/4`) . `2/3` - `5/12` . `3/10`
= `1/4` . `2/3` - `5/12` . `3/10`
= `1/6` - `1/8`
= `1/24`
c) `7/3` . `2/7` - `2/7` . `10/3` - `2/7`
= `7/3` . `2/7` - `2/7` . `10/3` - `2/7` . 1
= `2/7` . ( `7/3` - `10/3` - `1`)
= `2/7` . ( -1 - 1)
= `2/7` . (-2)
= `-4/7`
bài 2 )
a) `1/3` `x` - `5/2` = `-3`
`1/3` `x` = `-3` + `5/2`
`1/3` `x` = `-1/2`
`x` = `-1/2` : `1/3`
`x` = `-1/2` . `3/1`
`x` = `-3/2`
b) | 2 - 3`x` | = 5
⇒ 2 - 3`x` = 5 hoặc 2 - 3`x` = -5
3`x` = `2` - 5 hoặc 3`x` = `2` - ( -5 )
3`x` = `-3` hoặc 3 `x` = 7
`x` = `-3` : 3 hoặc `x` = 7 : 3
`x` = -1 hoặc `x` = `7/3`
