Which function vertex form is equivalent to f(x)=x^2+6x+3?

y = (x + 3)² - 6

Step-by-step explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Given

f(x) = x² + 6x + 3

Using the method of completing the square

add/subtract ( half the coefficient of the x- term)² to x² + 6x

f(x) = x² + 2(3)x + 9 - 9 + 3

     = (x + 3)² - 6 ← in vertex form