1. The problem statement, all variables and given/known data give the matrix in the transformation T in each case: T: is a reflection in the line y= -x 2. Relevant equations none that i know of for this question 3. The attempt at a solution i know y= -x goes from the top left to bottom right in a cartesian plane, so the reflection of the line with initial point (1,1) in the first quadrant would end up in the third quadrant. i get my answer as: -1 0 0-1 but the answer in the back of the book is: 0 -1 -1 0 why is their matrix the exact opposite as mine?