Giải thích các bước giải:
\(\begin{array}{l}
a.DK:x \ge 0;x \ne \frac{1}{4}\\
P \in Z\\
\Leftrightarrow \frac{{4\sqrt x - 1}}{{2\sqrt x + 1}} \in Z\\
\Leftrightarrow \frac{{2\left( {2\sqrt x + 1} \right) - 3}}{{2\sqrt x + 1}} \in Z\\
\Leftrightarrow \frac{3}{{2\sqrt x + 1}} \in Z\\
\Leftrightarrow \left( {2\sqrt x + 1} \right) \in U\left( 3 \right)\\
\to \left[ \begin{array}{l}
2\sqrt x + 1 = 3\\
2\sqrt x + 1 = - 3\left( l \right)\\
2\sqrt x + 1 = 1\\
2\sqrt x + 1 = - 1\left( l \right)
\end{array} \right. \to \left[ \begin{array}{l}
x = 1\left( {TM} \right)\\
x = 0\left( {TM} \right)
\end{array} \right.
\end{array}\)
