Answer:
vertex = (2, - 5 )
Explanation:
given a quadratic function
g(x) = ax² + bx + c ( a ≠ 0 )
then the x- coordinate of the vertex is
= -

given
g(x) = 3x² - 12x + 7
with a = 3 , b = - 12 , then
= -
= -
= - (- 2) = 2
to find the y- coordinate , evaluate g(2)
g(2) = 3(2)² - 12(2) + 7 = 3(4) - 24 + 7 = 12 - 17 = - 5
vertex = (2, - 5 )