X-5/-4 = -9/x-5 helpppppppppp

`#Chanh`

`( x - 5)/( - 4) = ( - 9)/( x - 5)`

`=> ( x - 5). ( x - 5) = ( - 4). ( - 9)`

`=> ( x - 5)^2 = 4. 9`

`=> ( x - 5)^2 = 36`

`=> 6^2 = 36; ( - 6)^2 = 36`

`=> x - 5 = 6 = - 6`

`=> x = 6 + 5; ( - 6) + 5`

`=> x  in { 11; -1)}`

Vậy : `x in { 11; -1}`