ANSWER
The vertex of g(x) is (2,-5).
EXPLANATION
The given function is:
[tex]g(x) = 3 {x}^{2} - 12x + 7[/tex]
The vertex form of this function is:
[tex]g(x) = 3 {(x - 2)}^{2} -5[/tex]
This is of the form
[tex]g(x) = a {(x - h)}^{2} + k[/tex]
where (h,k) is the vertex.
When we to
[tex]g(x) = 3 {(x - 2)}^{2} -5[/tex]
h=2 and k=-5
The vertex of the parabola is (2,-5).