Working with our Magma throwing Volcanos we are given the coordinates:

(2,0) and (8,0) with a Vertex of (5,3)

Our Intercept form is:

y = -1/3 (x-2)(x-8)

Our Vertex form is:

y = -1/3 (x-5)^2 + 3

Checking our work back to Standard is:

y = -1/3 (x-5)^2 + 3

y = -1/3 (x-5)(x-5) + 3

y = -1/3 (x^2 -5x -5x +25) + 3 – FOIL

y = -1/3 (x^2 -10x +25) + 3

y = -1/3x^2 + 10/3 -25/3 + 9/3

y = -1/3x^2 + 10/3 - 16/3