Answer:
y = 3(x + 3)² - 31
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
To obtain this form use the method of completing the square
take out a common factor of 3 from the first 2 terms
y = 3(x² + 6x) - 4
add/subtract ( half the coefficient of the x-term)² to x² + 6x
y = 3(x² + 2(3)x + 9 - 9 ) - 4
y = 3(x + 3)² - 27 - 4
y = 3(x + 3)² - 31 ← in vertex form