Question

Consider the function f(x) = x2 + 8x +1. Which equation shows function f written in vertex form?

f() = (x + 8)2 +1
f(x) = (x – 4)²+1
f(x) = (x – 8)² – 17
f()= (x +4)2 - 15​

Answer 1

4th option

Explanation:

f(x) = x² + 8x + 1

using the method of completing the square

add/subtract ( half the coefficient of the x- term )² to x² + 8x

f(x) = x² + 2(4)x + 16 - 16 + 1

= (x + 4)² - 15 ← in vertex form