`{2- x}/4= {3x- 1}/-3` `{12- 3x}/32= {6}/{4- x}`

Các bước giải:

`(2 -x)/4 = (3x -1)/-3`

`⇒ -3.(2 -x) = 4.(3x -1)`

`⇒ -6 +3x = 12x -4`

`⇒ -9x = 6`

`⇒ x = -2/3`

Vậy `x = -2/3`

——————

`(12 -3x)/32 = 6/(4 -x)` `(ĐKXĐ:` `x ne 4)`

`⇒ (12 -3x).(4 -x) = 32.6`

`⇒ 48 -24x +3x² = 192`

`⇒ 3x² -24x -144 = 0`

`⇒ 3x.(x -12) +12.(x -12) = 0`

`⇒ (x -12).(3x +12) = 0`

$⇒ \left[ \begin{array}{l}x -12=0\\3x +12=0\end{array} \right. ⇒ \left[ \begin{array}{l}x=12\\x=-4\end{array} \right.$ $(T/m$ `đkxđ)`

Vậy `x ∈ {12; -4}`