Answer:
The function is equal to [tex]y=-(1/4)(x-8)^{2}-1[/tex]
Step-by-step explanation:
we know that
The equation of a vertical parabola in vertex form is equal to
[tex]y=a(x-h)^{2}+k[/tex]
where
a is a coefficient
(h,k) is the vertex
In this problem we have
(h,k)=(8,-1)
substitute
[tex]y=a(x-8)^{2}-1[/tex]
Find the value of a
Remember that we have the y-intercept
The y-intercept is the point (0,-17)
substitute
x=0,y=-17
[tex]-17=a(0-8)^{2}-1[/tex]
[tex]-17=64a-1[/tex]
[tex]64a=-17+1[/tex]
[tex]64a=-16[/tex]
[tex]a=-16/64[/tex]
[tex]a=-1/4[/tex]
therefore
The function is equal to
[tex]y=-(1/4)(x-8)^{2}-1[/tex]
see the attached figure to better understand the problem