Đáp án:
\(x = \dfrac{{51a - 15}}{{2a\left( {a - 3} \right)\left( {a + 3} \right)}}\)
Giải thích các bước giải:
\(\begin{array}{l}
x + 3 + \dfrac{{4 - 3{a^2}}}{{\left( {a - 3} \right)\left( {a + 3} \right)}} = \dfrac{5}{{2a\left( {a + 3} \right)}}\\
\to x = \dfrac{5}{{2a\left( {a + 3} \right)}} - \dfrac{{4 - 3{a^2}}}{{\left( {a - 3} \right)\left( {a + 3} \right)}} - 3\\
= \dfrac{{5\left( {a - 3} \right) - 2a\left( {4 - 3{a^2}} \right) - 3.2a\left( {{a^2} - 9} \right)}}{{2a\left( {a - 3} \right)\left( {a + 3} \right)}}\\
= \dfrac{{5a - 15 - 8a + 6{a^3} - 6{a^3} + 54a}}{{2a\left( {a - 3} \right)\left( {a + 3} \right)}}\\
= \dfrac{{51a - 15}}{{2a\left( {a - 3} \right)\left( {a + 3} \right)}}
\end{array}\)
