Question

The first three steps in writing f(x) = 40x + 5x2 in vertex form are shown.

Write the function in standard form. f(x) = 5x² + 40x
Factor a out of the first two terms. f(x) = 5(x2 + 8x)
Form a perfect square trinomial.
* = 16
f(x) = 5(x2 + 8x + 16) - 5(16)
What is the function written in vertex form?
f(x) = 5(x + 4) - 80
f(x) = 5(X + 8) - 80
f(x) = 5(x + 4)2 – 80
f(x) = 5(X + 8)2 - 80

Answer 1

C) f(x) = 5(x + 4)² - 80

Explanation:

I did the Unit Test and it was correct on Edg. 2021

Answer 2

f(x) = 5(x + 4)² - 80

Explanation:

f(x) = 5(x² + 8x + 16) - 5(16)

f(x) = 5(x + 4)² - 80

The function written in vertex form is

f(x) = 5(x + 4)² - 80

The graph of ƒ(x) is shown below. The axis of symmetry is x = -4, the vertex is at (-4, -80), the and the roots are at (-4,0) and (0, 0).