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Điều kiện : $\left\{ \begin{array}{l} 1 \ne 2x - 1 > 0\\ 1 \ne {x^2} - 3x + 2 > 0 \end{array} \right.$ $ \Leftrightarrow \left\{ \begin{array}{l} 1 \ne x > \frac{1}{2}\\ x < 1\,\,\,\,;\,x > 2\\ x \ne \frac{{3 \pm \sqrt 5 }}{2} \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\, \Leftrightarrow \left\{ \begin{array}{l} \frac{1}{2} < x < 1\\ x > 2\,\,\,\,\ x \ne \frac{{3 \pm \sqrt 5 }}{2}\,\,\,\,\,(*) \end{array} \right.$ $\begin{array}{l} (1) \Leftrightarrow - \frac{1}{{{{\log }_2}\left( {2x - 1} \right)}} + \frac{1}{{{{\log }_2}\sqrt {{x^2} - 3x + 2} }} > 0\,\,\,\,\\ \,\,\,\,\,\, \Leftrightarrow \left\{ \begin{array}{l} {\log _2}\left( {2x - 1} \right).{\log _2}\sqrt {{x^2} - 3x + 2} > 0\\ {\log _2}\left( {2x - 1} \right) > {\log _2}\sqrt {{x^2} - 3x + 2} \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2) \end{array}$ Hoặc $\left\{ \begin{array}{l} {\log _2}\left( {2x - 1} \right) < 0\\ {\log _2}\sqrt {{x^2} - 3x + 2} > 0 \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(3)$ giải ($2$) : $(2) \Leftrightarrow \,\,\,\,\,\,\,\,\left\{ \begin{array}{l} \sqrt {{x^2} - 3x + 2} > 1\\ 2x - 1 > \sqrt {{x^2} - 3x + 2} \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(4)$ Hoặc $\left\{ \begin{array}{l} 2x - 1 < 1\\ 2x - 1 > \sqrt {{x^2} - 3x + 2} \end{array} \right.\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(5)$ $(4) \Leftrightarrow \left\{ \begin{array}{l} {x^2} - 3x + 1 > 0\\ 3{x^2} - x - 1 > 0 \end{array} \right.\,\,\,\,\, \Leftrightarrow \left\{ \begin{array}{l} x < \frac{{3 - \sqrt 5 }}{2}\,\,\,;x > \frac{{3 + \sqrt 5 }}{2}\\ x < \frac{{1 - \sqrt {13} }}{6}\,;\,x > \frac{{1 + \sqrt {13} }}{6} \end{array} \right.$ Xét các điều kiện ($*$) ta có $x > \frac{{3 + \sqrt 5 }}{2}$ $(5) \Leftrightarrow \left\{ \begin{array}{l} x < 1\\ 3{x^2} - x - 1 > 0 \end{array} \right.\,\,\,\,\,\, \Leftrightarrow \left\{ \begin{array}{l} x < 1\\ x < \frac{{1 - \sqrt {13} }}{6}\,\,;\,\,x > \frac{{1 + \sqrt {13} }}{6} \end{array} \right.$ Đối chiếu với điều kiện ($*$) ta có ($5$) vô nghiệm giải ($3$) : $(3) \Leftrightarrow \left\{ \begin{array}{l} 0 < 2x - 1 < 1\\ {x^2} - 3x + 1 > 0 \end{array} \right.\,\,\,\,\,\,\, \Leftrightarrow \left\{ \begin{array}{l} \frac{1}{2} < x < 1\\ x < \frac{{3 - \sqrt 5 }}{2}\,\,\,\,;\,x > \frac{{3 + \sqrt 5 }}{2} \end{array} \right.$ Hệ này vô nghiệm Vậy nghiệm của ($1$) là $x > \frac{{3 + \sqrt 5 }}{2}$
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