How can I get a quadratic equation in vertex form with only my x-intercepts and vertex?

Question

I need to find the equation in vertex form for a parabola but I am so lost

The vertex is (9,17)

The x-intercepts are (0,0) and (18,0)

 

Thanks :)

Answer 1

f(x) = a(x - 9)² + 17 vertex form

0 = a(0 - 9)² + 17 substituting (0, 0)

0 = 81a + 17

-17 = 81a

-17/81 = a

f(x) = (-17/81)(x - 9)² + 17

Answer 2

TL;DR: y = -.21(x-9)^2+17