Tìm x biết: a) x - 7/12 = 16/9 . -3/8 ;

* Hướng dẫn giải

$\mathrm{a})\hspace{0.17em}\mathrm{x}-\frac{7}{12}=\frac{16}{9}.\frac{-3}{8}$

$$\begin{gathered} \mathrm{x}-\frac{7}{12}=\frac{8.2}{3.3}.\frac{-3}{8} \\ \mathrm{x}-\frac{7}{12}=\frac{-2}{3} \\ \mathrm{x}=\frac{-2}{3}+\frac{7}{12} \\ \mathrm{x}=\frac{-2.4}{3.4}+\frac{7}{12} \end{gathered}$$

$$\begin{gathered} \mathrm{x}=\frac{-8}{12}+\frac{7}{12} \\ \mathrm{x}=\frac{-1}{12} \\ \mathrm{Vậy} \mathrm{x}=\frac{-1}{12} \end{gathered}$$