Let's begin by listing out the information given:
A (-1, 0); B (-3, 0); C (-1, 3)
E (2, -3); D (2, -5); F (5, -3)
A = E; B = D; C = F
A (-1, 0) = E (2, -3) = (2--1, -3-0) = (3, -3)
B (-3, 0) = D (2, -5) = (2--3, -5-0) = (5, -5)
C (-1, 3) = F (5, -3) = (5--1, -3-3) = (6, -6)
We observe that x = -y or y = -x