Question

Write the equation of the quadratic function with roots -9 and and -3 and a vertex at (-6, -1).

Answer 1

use y=a(x-h)^2 +k
plug in the vertex (h,k) to get
y=a(x+6)^2 -1
then take on of the roots (-9,0) or (-3,0) and plug in to find a
0=a(-3+6)^2 -1 to get that a=1/9
so the equation is
y=(1/9)(x+6)^2 -1