x-15/15 + x-74/13 + x-67/11 + x-64/9 = 10

$\text{Mình sửa đề 1 chút nhé!}$

`(x-85)/15 + (x-74)/13 + (x-67)/11 + (x-64)/9 = 10`

`⇒ (x-85)/15 + (x-74)/13 + (x-67)/11 + (x-64)/9 – 10 = 0`

`⇒ ((x-85)/15 – 1) + ((x-74)/13 -2) + ((x-67)/11 – 3) + ((x-64)/9 – 4) = 0`

`⇒ (x-100)/15 + (x-100)/13 + (x-100)/11 + (x-100)/9 = 0`

`⇒ (x-100).(1/15 + 1/13 + 1/11 + 1/9) = 0`

`Vì` `(1/15+1/13 + 1/11 + 1/9) \ne 0`

`⇒ x – 100 = 0`

`⇒ x = 100`