Answer:
vertex = (4, 9 )
Explanation:
the equation of a parabola in vertex form is
f(x) = a(x - h)² + k
where (h, k ) are the coordinates of the vertex and a is a multiplier
f(x) = 3(x - 4)² + 9 ← is in vertex form
with h = 4 and k = 9 , then
vertex = (4, 9 )