Question

What is the vertex for the graph of y = 3x2 - 12x + 9?
Answer
(-2, 21)
(-2, 45)
(2, -3)
(2, -9)

Answer 1

formula of parabola: y=ax^2+bx+c
vertex: (x,y)

now, x=-b/2a
with the given expression, x=-(-12)/2(3)=2
substitute the value of x to the expression, y=3(2)^2-12(2)+9=-3

vertex: (2, -3) :)