a) Ta có : \(A(1;3);\;B(-3;1);\;C(-2;2)\)
$\begin{array}{l}
\Rightarrow \overrightarrow {AB} = \left( { - 3 - 1;\,\,1 - 3} \right) = \left( { - 4; - 2} \right)\\
\,\,\,\,\,\,\,\overrightarrow {CA} = \left( {1 - ( - 2);\,\,3 - 2} \right) = \left( {3;1} \right)\\
\,\,\,\,\,\,\overrightarrow {CB} = \left( { - 3 - ( - 2);\,\,1 - 2} \right) = \left( { - 1; - 1} \right)
\end{array}$
b)
\(\begin{array}{l}
Goi\,D\left( {x;y} \right) \Rightarrow \overrightarrow {DC} = \left( { - 2 - x;2 - y} \right)\\
ABCD\,la\,hbh \Leftrightarrow \overrightarrow {AB} = \overrightarrow {DC} \\
\Leftrightarrow \left\{ \begin{array}{l}
- 2 - x = - 4\\
2 - y = - 2
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = 2\\
y = 4
\end{array} \right. \Rightarrow D\left( {2;4} \right)
\end{array}\)
