Answer:
vertex = (- 1, 0 )
Step-by-step explanation:
Given a parabola in standard form
f(x) = ax² + bx + c ( a ≠ 0 )
Then the x- coordinate of the vertex is
x = - [tex]\frac{b}{2a}[/tex]
f(x) = 3x² + 6x + 3 ← is in standard form
with a = 3, b = 6 , then
[tex]x_{vertex}[/tex] = - [tex]\frac{6}{6}[/tex] = - 1
Substitute x = - 1 into f(x) for corresponding y- coordinate of vertex
f(- 1) = 3(- 1)² + 6(- 1) + 3 = 3(1) - 6 + 3 = 3 - 6 + 3 = 0
vertex = (- 1, 0 )