Giá trị nào dưới đây của xx thỏa mãn 

A

- Hướng dẫn giải

 \(\begin{array}{l}4x + 5\dfrac{1}{5}x = \dfrac{{27}}{{25}}\\4x + \dfrac{{26}}{5}x = \dfrac{{27}}{{25}}\\x.\left( {4 + \dfrac{{26}}{5}} \right) = \dfrac{{27}}{{25}}\\x.{\dfrac{{46}}{5}} = \dfrac{{27}}{{25}}\\x = \dfrac{{27}}{{25}}:\dfrac{{46}}{5}\\x = \dfrac{{27}}{{25}}.\dfrac{5}{{46}}\\x = \dfrac{{27}}{{230}}\end{array}\)