You're simply asking where point 'B' winds up after the translation,
so we don't care about triangles or about point-'A'. None of that
is relevant to this particular question.
-- 'B' started out at (1, 5) .
-- Translating 6 units up makes the y-coordinate bigger by 6 .
-- Translating 3 units to the left makes the x-coordinate less by 3 .
-- So point-'B' ends up at (1-3, 5+6) = (-2, 11) .
