`a) 1/2 x - 1/3 = 5/6`
`1/2 x = 5/6 + 1/3`
`1/2 x = 7/6`
`x = 7/6 : 1/2`
`x = 7/3`
Vậy `x = 7/3`
`b) 7/12 - ( x + 7/10) : 1 1/5 = -5/4`
`( x + 7/10) : 6/5 = 7/12 - (-5/4)`
`( x + 7/10) : 6/5 = 11/6`
`( x + 7/10) = 11/6 . 6/5`
` x + 7/10 = 11/5`
`x = 11/5 - 7/10`
`x= 3/2`
Vậy `x = 3/2`
`c) | x - 1/2| - 1/5 = 0`
`| x - 1/2| = 0 + 1/5`
`|x - 1/2| = 1/5`
⇒ ` x - 1/2 = 1/5`
`x = 1/5 + 1/2`
`x = 7/10`
`+) x - 1/2 = -1/5`
`x = -1/5 + 1/2`
`x =3/10`
Vậy `x ∈ { 7/10 ; 3/10}`
`d) ( x - 1/3)( 2 - 3/4x) = 0`
⇒ `x - 1/3 = 0` hoặc `2 - 3/4x = 0`
`x = 0 + 1/3` hoặc `3/4 x = 2 - 0`
`x = 1/3` hoặc `3/4 x = 2`
`x = 1/3` hoặc `x = 2 : 3/4`
`x = 1/3` hoặc `x = 8/3`
Vậy `x∈ { 1/3 ; 8/3}`