问题647: The graph showed a parabola 𝑦 = 𝑎(𝑥 − ℎ) 2 +

The graph showed a parabola 𝑦 = 𝑎(𝑥 − ℎ)
2 + 𝑘. It has a vertex P,
and it intersects 𝑥-axis at A and B, given that the co-ordinates of A
and P are (−5,0) and (−3, −8). Find
(a) the value of 𝑎 ;
(b) the co-ordinates of B.