Identify the zeros, vertex and axis of symmetry of
y=-1/3(x+7)(x+1)
x^2 + 8 x + 1 = -3y
x^2 + 8 x = -3y - 1
x^2 + 8 x + 16 = -3 y + 15
(x+4)^2 = -3 (y-5)
vertex at (-4,5)
symmetric about x = -4
y = 0 when (x+4)^2 = 15
x+4 = +/- sqrt 15
x = -4 +/- sqrt 15 are the zeros