Point B(-3,7) is reflected across the line y=-x and then dilated with a scale factor of 3 and the center of dilation at the origin. What are the coordinates of point B" under the composition of transformations

Answer 1

under reflection in y = -x
(-3,7) ----> (-7,3)

with a dilation of 3 at the origin
(x,y) --->(3x,3y)
(-7,3) ----> (-21,9)