Ответ:

[tex] \displaystyle \frac{12}{x - 4} = - \frac{2}{3} .[/tex]

ОДЗ: х≠4.

[tex]12 \times 3 = - 2(x - 4) \\ - 2x + 8 = 36 \\ - 2x = 36 - 8 \\ - 2x = 28 \\ x = 28 \div ( - 2) \\ \boxed{x = - 14}.[/tex]