Tìm x, biết: 2/3 : x = 1,4 -12/5

* Hướng dẫn giải

$$\begin{gathered} \frac{2}{3}:\mathrm{x}=1,4-\frac{12}{5} \\ \frac{2}{3}:\mathrm{x}=\frac{14}{10}-\frac{12}{5} \\ \frac{2}{3}:\mathrm{x}=\frac{7}{5}-\frac{12}{5} \\ \frac{2}{3}:\mathrm{x}=-\frac{5}{5} \\ \frac{2}{3}:\mathrm{x}=-1 \\ \mathrm{x}=\frac{2}{3}:\left(-1\right) \\ \mathrm{x}=\frac{-2}{3} \\ \mathrm{Vậy} \mathrm{x}=\frac{-2}{3} \end{gathered}$$