a) Ta có:

`(3/2 - 2/(-5) ) : x - 1/2 = 3/2`

`(15/10 - (-4)/10 ) : x = 3/2 + 1/2`

`19/10 : x = 2`

`x = 19/10 : 2`

`x= 19/20`

b) Ta có:

`(5x - 1) - (2x + 1/3) = 0`

`5x - 1 - 2x - 1/3 = 0`

`3x - 4/3 = 0`

`3x = 4/3`

`x = 4/9`

c) Ta có:

`(x - 6)/1998 + (x - 4)/2000 = (x - 2000)/4 + (x - 1998)/6`

`(x - 6)/1998 -1 + (x - 4)/2000-1 = (x - 2000)/4-1 + (x - 1998)/6-1`

`(x - 2004)/1998 + (x - 2004)/2000 = (x - 2004)/4 + (x - 2004)/6`

`(x - 2004)/1998 + (x - 2004)/2000 - (x - 2004)/4 - (x - 2004)/6=0`

`(x-2004) (1/1998 + 1/2000 - 1/4 - 1/6)=0`

`to` x-2004 = 0 (vì `1/1998 + 1/2000 - 1/4 - 1/6` $\neq$ 0)

`to` x = 2004

`color{lightblue}{bigshark}`