The correct answer is B. a reflection over the x-axis followed by (x, y) → (x + 7, y + 3).
To transform ∆ABC to ∆A”B”C”, we need to consider the following steps:
Horizontal Shift: ∆ABC is shifted 3 units to the right, which can be achieved by the transformation (x, y) → (x + 3, y).
Vertical Shift: ∆ABC is shifted 7 units downward, which can be achieved by the transformation (x, y) → (x, y - 7).
Reflection over the x-axis: Since ∆A”B”C” is reflected across the x-axis, we need to negate the y-coordinate. This can be achieved by the transformation (x, y) → (x, -y).
Combining these transformations, we get the sequence:
(x, y) → (x + 3, y) → (x, y - 7) → (x, -y)
Therefore, the correct answer is B. a reflection over the x-axis followed by (x, y) → (x + 7, y + 3).