Đáp án:
Đặt x^2+x-2=a
\[\begin{array}{l}
{9^{a + 1}} - {10.3^a} - 9 = 0\\
< = > 9.{({3^a})^2} - {10.3^a} - 9 = 0\\
< = > \left[ \begin{array}{l}
{3^a} = \frac{{5 + \sqrt {106} }}{9}\\
{3^a} = \frac{{5 - \sqrt {106} }}{9}
\end{array} \right. = > \left[ \begin{array}{l}
a = {\log _3}\frac{{5 + \sqrt {106} }}{9}\\
a = {\log _3}\frac{{5 - \sqrt {106} }}{9}
\end{array} \right.\\
= > x
\end{array}\]
