Question

What’s the vertex of the quadratic function f(x)=(x-8)(x-2)

Answer 1

The vertex would be ( 5, - 2 ) :D

Answer 2

The zeros are at x=8 and x=2. The x-coordinate of the vertex is halfway between, at
x = (8+2)/2 = 5
The y-coordinate of the vertex is f(5) = (5-8)(5-2) = -9

The vertex of f(x) is (5, -9).