A Triangle with Vertices at (X1, Y1), (X2, Y2), and (X3

Multiple Choice

A triangle with vertices at (x1, y1) , (x2, y2) , and (x3, y3) has area equal to the absolute value of D, where $$D = \frac { 1 } { 2 } \left| \begin{array} { l l l } x _ { 1 } & y _ { 1 } & 1 \\x _ { 2 } & y _ { 2 } & 1 \\x _ { 3 } & y _ { 3 } & 1\end{array} \right|$$ Find the area of the triangle having vertices at P, Q, and R.
- $$\mathrm { P } ( - 3 , - 3 ) , \mathrm { Q } ( 0,0 ) , \mathrm { R } ( 5 , - 1 )$$

A) 12
B) 18
C) 0
D) 9