Hãy tìm x biết ​\(\left( {\frac{5}{{12}} - x} \right) \cdot \frac{5}{7} = - \frac{{15}}{{36}}\)

* Hướng dẫn giải

 \(\begin{aligned} &\left( {\frac{5}{{12}} - x} \right) \cdot \frac{5}{7} = - \frac{{15}}{{36}}\\ &\frac{5}{{12}} - x = - \frac{{15}}{{36}}:\frac{5}{7}\\ &\frac{5}{{12}} - x = - \frac{7}{{12}}\\ &x = \frac{5}{{12}} - \left( { - \frac{7}{{12}}} \right)\\ &x = \frac{{12}}{{12}}\\ &x = 1 \end{aligned}\)