Question

The zeros of a quadratic function are -6 and -2. What is a possible vertex of the function? EXPLAIN YOUR ANSWER AND SHOW YOUR WORK PLEASE.

A. (-4, -3)
B. (4, -2)
C. (4, 6)
D. (8, -4)

Answer 1

(-4,-4)

Explanation:

If the zeros of a quadratic function are -6 and -2, then it is:

(x+6)(x+2)

Expanding:

(x+6)(x+2)

=x^2+8x+12

To find the vertex, complete the square.

x^2+8x+12

=(x^2+8x+16)-16+12

=(x+4)^2-4

When the quadratic formula is written in the form y = a(x-h)^2+k, the vertex is (h, k).

(h, k)=(-4,-4)