Answer:
y = 3(x - 2)² - 8
Explanation:
The equation of a quadratic 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
• The coefficient of the x² term must be 1
Factor out 3 from the first 2 terms
y = 3(x² - 4x ) + 4
• add/subtract (half the coefficient of the x- term )² to x² - 4x
y = 3(x² + 2(- 2)x + (- 2)² - (- 2)² ) + 4 ← complete the square
y = 3(x - 2)² - 12 + 4
y = 3(x - 2)² - 8 ← in vertex form