What is the vertex form of

f(x) = x2 + 6x + 8 ?

(Hint: Complete the square.)

A f(x) = (x - 3)2 + 1
B. f(x) = (x + 3)2 + 17
C. f(x) = (x + 6)2 + 8
D. f(x) = (x + 3)2 - 1​