\[\begin{array}{l}a)\,2x\left( {x - \frac{1}{7}} \right) = 0\\ \Leftrightarrow \left[ \begin{array}{l}x = 0\\x - \frac{1}{7} = 0\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}x = 0\\x = \frac{1}{7}\end{array} \right.\\b)\,3,2x + \left( {1,2} \right).x + 2,7 = - 4,9\\ \Leftrightarrow 4,4x = - 4,9 - 2,7\\ \Leftrightarrow 4,4x = - 7,6\\ \Leftrightarrow x = - 7,6:4,4\\ \Leftrightarrow x = \frac{{19}}{{11}}\end{array}\]
\(\begin{array}{l}c)\,\frac{{37 - x}}{x} + 13 = \frac{3}{7}???\\d)\,\left| {x - 1,5} \right| + \left| {2,5 - x} \right| = 0\\ \Leftrightarrow \left\{ \begin{array}{l}x - 1,5 = 0\\2,5 - x = 0\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}x = 1,5\\x = 2,5\end{array} \right.\,\,\left( {vo\,ly} \right)\end{array}\)
Vậy không có giá trị nào của x thỏa mãn.
