Answer:
[tex]y = 3({x + 2)}^{2} + 8[/tex]
Step-by-step explanation:
The given function is
[tex]y = 3 {x}^{2} + 12x + 20[/tex]
Factor
[tex]y = 3({x}^{2} + 4x )+ 20[/tex]
Create a perfect square trinomial
[tex]y = 3({x}^{2} + 4x + 4 ) - 3 \times 4+ 20[/tex]
Factor the the perfect square
[tex]y = 3({x + 2)}^{2} - 12+ 20[/tex]
The vertex form is:
[tex]y = 3({x + 2)}^{2} + 8[/tex]