Đáp án:
\(\left[ \begin{array}{l}
x = 2\\
x = 3
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
DK:x \ne \pm 3\\
Pt \Leftrightarrow \frac{{ - 12}}{{\left( {x - 3} \right)\left( {x + 3} \right)}} + \frac{{2\left( {x + 3} \right)}}{{\left( {x - 3} \right)\left( {x + 3} \right)}} + \frac{{3\left( {x - 3} \right)}}{{\left( {x - 3} \right)\left( {x + 3} \right)}} = \frac{{{x^2} - 9}}{{\left( {x - 3} \right)\left( {x + 3} \right)}}\\
\Leftrightarrow - 12 + 2\left( {x + 3} \right) + 3\left( {x - 3} \right) = {x^2} - 9\\
\Leftrightarrow - 12 + 2x + 6 + 3x - 9 = {x^2} - 9\\
\Leftrightarrow {x^2} - 5x + 6 = 0\\
\Leftrightarrow \left( {{x^2} - 2x} \right) - \left( {3x - 6} \right) = 0\\
\Leftrightarrow x\left( {x - 2} \right) - 3\left( {x - 2} \right) = 0\\
\Leftrightarrow \left( {x - 2} \right)\left( {x - 3} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x - 2 = 0\\
x - 3 = 0
\end{array} \right.\\
\Leftrightarrow \left[ \begin{array}{l}
x = 2\left( {TMDKXD} \right)\\
x = 3\left( {KTMDKXD} \right)
\end{array} \right.
\end{array}\)
