Answer :
The dilation factor Sophia is using appears to be
(image coordinate)/(original coordinate) = -9/-3 = 15/5 = 3
Then the problem tells us
(pre-image point)×3 = (3, 1)
so we conclude
(pre-image point) = (3, 1)/3 = (1, 1/3)
(image coordinate)/(original coordinate) = -9/-3 = 15/5 = 3
Then the problem tells us
(pre-image point)×3 = (3, 1)
so we conclude
(pre-image point) = (3, 1)/3 = (1, 1/3)