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