[香港]Find the function

1. It is given that Q(5,k) is the vertex of the graph of the function
y=-x^2+10x-17.
Find the maximum value of the function
2. It is given
that P(h,6) us the vertex if the graph of the function y=x^2-6x+15

(a).
Find the value of h.
(b). Find the axis of symmetry of the graph

 

原連結


1. y= -x^2+10x-17= -(x-5)^2+8,
vertex(5,8)=Q(5,k),
k=8

2.y=x^2-6x+15=(x-3)^2+6,
(a)vertex(3,6)=P(h,6), h=3

(b)the axis of symmetry of the graph: x-3=0

ps. symmetry<> symmery