$\Delta=\frac{1}{2}\left|\begin{array}{ccc}-2 & -3 & 1 \\ 3 & 2 & 1 \\ -1 & -8 & 1\end{array}\right|$
$=\frac{1}{2}[-2(2+8)+3(3+1)+1(-24+2)]$
$=\frac{1}{2}[-2(10)+3(4)+1(-22)]$
$=\frac{1}{2}[-20+12-22]$
$=-\frac{30}{2}=-15$
Hence, the area of the triangle is $|-15|=15$ square units