Answer:
[tex]\left[\begin{array}{ccc}-3&3&3\\3&6&3\end{array}\right][/tex]
Step-by-step explanation:
Reflection over the line y=x is described by the transformation ...
(x, y) ⇒ (y, x)
The corresponding transformation matrix is ...
[tex]\left[\begin{array}{cc}0&1\\1&0\end{array}\right][/tex]
When this left-multiplies the given coordinate matrix, the result is the one shown above.
