tìm x biết a.11/8-13/6=85/x b.x+7/8=13/12 c.x+ -6/15=4/27 giúp em em vote 5 sao ạ

a) 11/8 - 13/6 = 85/x    

          -19/24  = 85/x

  =>      -19.x  = 24 . 85

             -19.x  = 2040

                   x  = 2040 : ( -19 )

                   x  = -2040/19

             vậy x  = 2040/-19

b) x + 7/8 = 13/12

    x           = 13/12-7/8

    x           = 5/24

        vậy x =5/24

c) x+  -6/15  = 4/27

    x               = 4/27-  -6/15

    x               = 4/27+ 6/15

    x               = 74/135

              vậy x  =74/135

Answer

`a, 11/8 - 13/6 = 85/x`

`=> {-19}/24 = 85/x`

`=> -19x = 24 . 85`

`=> -19x = 2040`

`=> x = 2040 : (-19)`

`=> x = {-2040}/19`

Vậy `x = {-2040}/19`

_____________________________

`b, x + 7/8 = 13/12`

`=> x = 13/12 - 7/8`

`=> x = 5/24`

Vậy `x = 5/24`

_____________________________

`c, x + {-6}/15 = 4/27`

`=> x = 4/27 + 6/15`

`=> x = 74/135`

Vậy `x = 74/135`