Bất phương trình \(\sqrt {...

A

- Hướng dẫn giải

\(\begin{array}{l}
BPT \Leftrightarrow \left[ \begin{array}{l}
\left\{ \begin{array}{l}
 - {x^2} + 6x - 5 \ge 0\\
8 - 2x < 0
\end{array} \right.\\
\left\{ \begin{array}{l}
8 - 2x \ge 0\\
 - {x^2} + 6x - 5 > {\left( {8 - 2x} \right)^2}
\end{array} \right.
\end{array} \right.\\
 \Leftrightarrow \left[ \begin{array}{l}
\left\{ \begin{array}{l}
1 \le x \le 5\\
x > 4
\end{array} \right.\\
\left\{ \begin{array}{l}
x \le 4\\
3 < x < \frac{{23}}{5}
\end{array} \right.
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
4 < x \le 5\\
3 < x \le 4
\end{array} \right.\\
 \Leftrightarrow 3 < x \le 5
\end{array}\)