Rotate the given triangle 90°
counter-clockwise about the
origin [ 0 -3 5]
[0 1 2 ]

9514 1404 393
Answer:
[tex]\left[\begin{array}{ccc}0&-1&-2\\0&-3&5\end{array}\right][/tex]
Step-by-step explanation:
The rotation matrix for 90° CCW is ...
[tex]\left[\begin{array}{cc}0&-1\\1&0\end{array}\right][/tex]
Then the rotated coordinates are ...
[tex]\left[\begin{array}{ccc}0&-1\\1&0\end{array}\right]\cdot\left[\begin{array}{ccc}0&-3&5\\0&1&2\end{array}\right]=\left[\begin{array}{ccc}0&-1&-2\\0&-3&5\end{array}\right][/tex]
_____
The transformation of each ordered pair is ...
(x, y) ⇒ (-y, x)