The function f (x) = 3x² + 12x + 11 can be written in

vertex form as

1) f (x) = (3x + 6) ² - 25

2) f (x) = 3 (x + 6) ^2 - 25

3) f (x) = 3 (x + 2) ² - 1

4) f (x) = 3 (x + 2) ² + 7

3) f (x) = 3 (x + 2) ^2 - 1.

Step-by-step explanation:

f (x) = 3x² + 12x + 11

f (x) = 3 (x^2 + 4x) + 11 Completing the square:

f (x) = 3[ (x + 2) ^2 - 4] + 11

f (x) = 3 (x + 2) ^2 - + 3*-4 + 11

f (x) = 3 (x + 2) ^2 - 12 + 11

f (x) = 3 (x + 2) ^2 - 1.