c) 9/8 -4/7x = 1/8

* Hướng dẫn giải

$\begin{array}{l}\mathrm{c}) \frac{9}{8}-\frac{5}{7}\mathrm{x}=\frac{1}{8}\\ \frac{5}{7}\mathrm{x}=\frac{9}{8}-\frac{1}{8}\\ \frac{5}{7}\mathrm{x}=\frac{8}{8}\\ \mathrm{x}=1:\frac{5}{7}\\ \mathrm{x}=\frac{7}{5}\\ \mathrm{Vậy} \mathrm{x}=\frac{7}{5}\end{array}$