Giải pt : a. x-29/1970 + x-27/1972+x-25/1974 - 3 =0

`(x - 29)/1970 + (x - 27)/1972 - (x - 25)/1974 - 3 = 0`

`=>(x - 29)/1970 - 1 + (x - 27)/1972 - 1 + (x - 25)/1974 - 1=0`

`=>(x - 29 - 1970)/1970 + (x - 27 - 1972)/1972+(x - 25 - 1974)/1974 = 0`

`=>(x - 29 - 1970)/1970 + (x - 27 - 1972)/1972+(x - 25 - 1974)/1974 = 0`

`Rightarrow(x-1999). (1/1970 + 1/1972 + 1/1974) = 0`

`x - 1999 = 0 (do 1/1970 + 1/1972 + 1 1974 ne0 )`

`Rightarrow x = 1999`

`Sad2006`