Reflections and verticies

Question

Write the coordinates of the vertices after a reflection across the line x = –4. S(-1, 1) T(2, 2) U(-1, 10) V(-4, 2)

Answer 1

Such transformation of (x, y) point: (x,y) → (- 8 - x, y).

So, S(- 1, 1) → S'(- 8 + 1, 1) = S'(- 7, 1)

T(2, 2) → T'(- 8 - 2, 2) = T'(- 10,2)

U(- 1, 10) → U'(- 8 + 1, 10) = U'(- 7, 10)

V(- 4, 2) → V'( - 8 + 4, 2) = V'(- 4, 2); or V' = V