Don completes the square for the equation x^2 + 6x + 3 = 0. Which of the following equations reveals the vertex of the parabola?

X² + 6x + 3 = 0

y = x² + 6x + 3

y - 3 = x² + 6x

6x ⇒ 6x / 2x = 3 ⇒ 3² = 9

y - 3 + 9 = x² + 6x + 9

y + 6 = (x+3) ²

y = (x+3) ² - 6

vertex of the parabola is (x+3) ²

y = (x+3) (x+3) - 6

y = x (x+3) + 3 (x+3) - 6

y = x² + 3x + 3x + 9 - 6

y = x² + 6x + 3