Question

What is the vertex for the graph of
y = 3x2 − 12x + 9?

Answer 1

(2, -3)

Answer 2

solve for y..

Answer 3

To find the x variable of the vertex, use -b/2a. Then plug that number in for x and solve for y.

Answer 4

\[(3x ^{2}-12x)+9\]
\[3(x ^{2}-4x)+9\]
\[3(x ^{2}-4x+4-4)+9\]
\[3(x-2)^{2}-12+9\]
\[3(x-2)^{2}-3\]
so the vertex is (2, -3)