a)`6/-36=x/-28`

`[-1]/6=x/-28`

`6.x=-1.(-28)`

`6.x=28`

`x=14/3`

Vậy `x=14/3`

b)`1 1/2:1/2=x:1/5`

`3/2. 2=x:1/5`

`3=x:1/5`

`x=3. 1/5`

`x=3/5`

Vậy `x=3/5`

c)`2,5:x=0,75:0,03(x ne 0)`

`2,5:x=25`

`x=2,5:25`

`x=0,1`(TMĐK)

Vậy `x=0,1`

d)`[0,2]/2=5/[6x+8]`(`x ne [-4]/3`)

`0,2.(6x+8)=2.5`

`1,2x+1,6=10`

`1,2x=8,4`

`x=7`(TMĐK)

Vậy `x=7`

e)`x^2/12=27/64`

`x^2.64=12.27`

`x^2.64=324`

`x^2=81/16`

`x^2=(±9/4)^2`

`x=9/4` hoặc `x=[-9]/4`

Vậy `x∈{9/2;[-9]/4}`

f)`12/[2|x-1|]=2/27(x ne 1)`

`2|x-1|.2=12.27`

`4|x-1|=324`

`|x-1|=81`

`x-1=81` hoặc `x-1=-81`

`x=82`(TMĐK) hoặc `x=-80`(TMĐK)

Vậy `x∈{82;-80}`