Question

B(7,8) and B’(-8,-7) represent a 90 degree clockwise rotation. true or false?

Answer 1

90 degree clockwise rotation is described by the matrix,

$\begin{bmatrix}0&1\\-1&0\\ \end{bmatrix}$

If you apply the matrix to the vector $B$ you get,

$\begin{bmatrix}0&1\\-1&0\\ \end{bmatrix}\begin{bmatrix}7\\8\\ \end{bmatrix}=\begin{bmatrix}7\cdot0+8\cdot1=8\\ -1\cdot7+8\cdot0=-7\\ \end{bmatrix}$

So false.

Hope this helps.