b) 1/4x + 3/8 (x-2) = -11/4

* Hướng dẫn giải

$\begin{array}{l}\mathrm{b}) \frac{1}{4}\mathrm{x}+\frac{3}{8}\left(\mathrm{x}-2\right)=-\frac{11}{4}\\ \frac{1}{4}\mathrm{x}+\frac{3}{8}\mathrm{x}-\frac{3}{8}.2=-\frac{11}{4}\\ \frac{2}{8}\mathrm{x}+\frac{3}{8}\mathrm{x}-\frac{3}{4}=-\frac{11}{4}\\ \frac{5}{8}\mathrm{x}=\frac{3}{4}-\frac{11}{4}\\ \frac{5}{8}\mathrm{x}=-\left(\frac{11}{4}-\frac{3}{4}\right)\\ \frac{5}{8}\mathrm{x}=-\frac{8}{4}\\ \frac{5}{8}\mathrm{x}=-2\\ \mathrm{x}=-2:\frac{5}{8}\\ \mathrm{x}=-2.\frac{8}{5}\\ \mathrm{x}=\frac{-16}{5}\\ \mathrm{Vậy} \mathrm{x}=\frac{-16}{5}\end{array}$