Đáp án:
$\begin{array}{l}
\frac{1}{{3x - 2}} - \frac{4}{{3x + 2}} - \frac{{3x - 6}}{{4 - 9{x^2}}}\\
= \frac{1}{{3x - 2}} - \frac{4}{{3x + 2}} + \frac{{3x - 6}}{{\left( {3x - 2} \right)\left( {3x + 2} \right)}}\\
= \frac{{3x + 2 - 4\left( {3x - 2} \right) + 3x - 6}}{{\left( {3x - 2} \right)\left( {3x + 2} \right)}}\\
= \frac{{3x + 2 - 12x + 8 + 3x - 6}}{{\left( {3x - 2} \right)\left( {3x + 2} \right)}}\\
= \frac{{4 - 6x}}{{\left( {3x - 2} \right)\left( {3x + 2} \right)}}\\
= \frac{{ - 2\left( {3x - 2} \right)}}{{\left( {3x - 2} \right)\left( {3x + 2} \right)}}\\
= \frac{{ - 2}}{{3x + 2}}
\end{array}$
