Answer
$26$ square units
Work Step by Step
We use the formula:
$Area=\dfrac{1}{2} |D|$, where $D=\begin{vmatrix}x_1&y_1&1\\x_2&y_2&1\\x_3&y_3&1\end{vmatrix}$
First compute $D$:
$D=\begin{vmatrix}1&1&1\\-2&-3&1\\11&-3&1\end{vmatrix}$
$=1\begin{vmatrix}-3&1\\-3&1\end{vmatrix}-1\begin{vmatrix}-2&1\\11&1\end{vmatrix}+1\begin{vmatrix}-2&-3\\11&-3\end{vmatrix}$
$=1(-3+3)-1(-2-11)+1(6+33)$
$=52$
Determine the area:
$Area=\dfrac{1}{2}\cdot 52=26$ square units
