Đáp án:

 `↓`

Giải thích các bước giải:

`b) (x-1)/(2015) + (x-3)/(2013) = (x-5)/(2011) + (x-7)/(2019)`

`=>  (x-1)/(2015) -1+ (x-3)/(2013)-1 = (x-5)/(2011) -1+ (x-7)/(2019) -1`

`=> (x-2016)/(2015) + (x-2016)/(2013) = (x-2016)/(2011) + (x-2016)/(2019)`

`=> (x-2016)/(2015) + (x-2016)/(2013) -(x-2016)/(2011) -(x-2016)/(2019) =0`

`=> (x-2016) . (1/(2015) + 1/(2013) - 1/(2011) - 1/(2019)) =0`

Mà `1/(2015) + 1/(2013) - 1/(2011) - 1/(2019) ne 0`

`=>x-2016=0`

`=>x=2016`

Vậy `x=2016`