Answer:
f(x) = 3(x + 1)² + 2
Step-by-step explanation:
Use the method of completing the square
3x² + 6x + 5
= 3(x² + 2x) + 5
add/ subtract (half the coefficient of the x-term)² to x² + 2x
= 3(x² + 2(1)x + 1 - 1) + 5
= 3(x + 1)² - 3 + 5
f(x) = 3(x + 1)² + 2 ← in vertex form
