Tìm x biết ​rằng \(\begin{array}{l} x\left( {4 + \frac{5}{2}} \right) + \frac{1}{6} = \frac{5}{4} \end{array}\)

* Hướng dẫn giải

 \(\begin{array}{l} x\left( {4 + \frac{5}{2}} \right) + \frac{1}{6} = \frac{5}{4}\\ \,x\left( {4 + \frac{5}{2}} \right) = \frac{5}{4} - \frac{1}{6}\\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{{13}}{2}x = \frac{{13}}{{12}}\\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x = \frac{{13}}{{12}}:\frac{{13}}{2}\\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x = \frac{{13}}{{12}} \cdot \frac{2}{{13}}\\ \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x = \frac{1}{6} \end{array}\)