2 câu trả lời
$\begin{array}{l} \left| {\frac{{x - 3}}{4}} \right| + \left| {\frac{2}{5} - y} \right| = 0\,\,\,\,\left( * \right)\\ Vi\,\,\,\left\{ \begin{array}{l} \left| {\frac{{x - 3}}{4}} \right| \ge 0\\ \left| {\frac{2}{5} - y} \right| \ge 0 \end{array} \right. \Rightarrow \left( * \right) \Leftrightarrow \left\{ \begin{array}{l} \frac{{x - 3}}{4} = 0\\ \frac{2}{5} - y = 0 \end{array} \right.\\ \Leftrightarrow \left\{ \begin{array}{l} x - 3 = 0\\ y = \frac{2}{5} \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} x = 3\\ y = \frac{2}{5} \end{array} \right.. \end{array}$
