Đáp án:
$\begin{array}{l}
a)\dfrac{{5 - 2x}}{3} = \dfrac{{4x - 1}}{{ - 5}}\\
\Rightarrow - 5.\left( {5 - 2x} \right) = 3.\left( {4x - 1} \right)\\
\Rightarrow - 25 + 10x = 12x - 3\\
\Rightarrow 12x - 10x = - 25 + 3\\
\Rightarrow 2x = - 22\\
\Rightarrow x = - 11\\
Vay\,x = - 11\\
)\dfrac{{12 - 3x}}{{32}} = \dfrac{6}{{4 - x}}\\
\Rightarrow 3\left( {4 - x} \right)\left( {4 - x} \right) = 6.32\\
\Rightarrow {\left( {4 - x} \right)^2} = 64\\
\Rightarrow \left[ \begin{array}{l}
4 - x = 8\\
4 - x = - 8
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = - 4\\
x = 12
\end{array} \right.\\
Vay\,x = - 4\,hoac\,x = 12\\
c)\dfrac{{10 - 2x}}{6} = \dfrac{{27}}{{5 - x}}\\
\Rightarrow \left( {10 - 2x} \right)\left( {5 - x} \right) = 6.27\\
\Rightarrow 2{\left( {5 - x} \right)^2} = 6.27\\
\Rightarrow {\left( {5 - x} \right)^2} = 81\\
\Rightarrow \left[ \begin{array}{l}
5 - x = 9\\
5 - x = - 9
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = - 4\\
x = 14
\end{array} \right.\\
Vay\,x = - 4\,hoac\,14
\end{array}$
