Question

What is the vertex of the quadratic function f(x) = (x-8)(x - 2)?

Answer 1

The vertex is (5, -9).

Explanation:

One way of approaching this problem consists of finding the roots. Seet the quadratic equal to zero and solve for x: {2, 8}.

The axis of symmetry is exactly halfway between 2 and 8: x = 5.

Now find the y-component of the vertex by evaluating f(5):

f(5) = (5 - 8)(5 - 2) = -9

The vertex is (5, -9). This is the minimum value of the function. The graph of this quadratic opens up.