y = -2(x - 5)^2 + 18
the vertex form is y = a(x - h)^2 + k
a = slope= -2 this slope tells us there is a maximum, the vertex it the top of the parabola.
Vertex is (h,k) = (5, 18)
axis of symetry is x = 5 or h
y = -2(x -5)^2 + 18
set x = 0 to get y-interrcept(s)
y = 18 (0,18)
set y = 0 to get the x-intercepts
0 = -2(x - 5)^2 + 18
-18/-2 = (x - 5)^2
3 = x - 5 or -3 = x - 5
x = 8 or x = 2
(8,0) and (2,0)