Answer:
b. (x - 2, y + 1)
Explanation:
You can make that determination visually. However, if you need numbers...
Pick a point on the black triangle, let's say F(0, 0) and the corresponding point on the blue tirangle F(-2, 1)
(y₁ + y₂) / (x₁ + x₂) = (0 + 1) / (0 + (-2)) = 1 / -2
=
So, from the F(0,0) position move -2 to the left then up 1 to land on F(-2, 1).
This translated to (x - 2, y + 1)