$S_{ΔABC}=\dfrac{1}{2}.AC.AB=207$
$↔\dfrac{1}{2}.(x-2)(x+3)=207$
$↔x²+x-6=414$
$↔x²+x-420=0$
$↔x²+2.\dfrac{1}{2}.x+\dfrac{1}{4}-\dfrac{1681}{4}=0$
$↔\bigg(x+\dfrac{1}{2}\bigg)²-\bigg(\sqrt{1681}{4}\bigg)²=0$
$↔(x-20)(x+21)=0$
\(\leftrightarrow\left[ \begin{array}{l}x-20=0\\x+21=0\end{array} \right.\) \(\leftrightarrow\left[ \begin{array}{l}x=20(tm)\\x=-21(ktm)\end{array} \right.\)
$\to \begin{cases}AB=18\\AC=23\end{cases}$
