Question

What are the coordinates of the vertex of the graph of the function y = –3x² –12x + 3?

Answer 1

huuurry C;

Answer 2

there are a couple of ways to do this

1. find the line of symmetry, the vertex lies on the line
for a quadratic

\[ax^2 +bx + c\]

the line of symmetry is

\[x = \frac{-b}{2a} \]

so in your question

\[x = \frac{12}{2 \times -3} ... so.. x = -2\]

substitute it into the equation for find the y value..

2. take out the common factor

\[y = -3(x^2 + 4x - 1)\]

complete the square on

\[x^2 + 4x \]

will give

\[y = -3((x^2 + 4x + 4) -5)\]

so

\[y = -3(x + 2) + 15 \]

the general form is

y = (x -h)^2 + k so the vertex is (h, k)

both methods give the same answer.

Answer 3

Thaank You So Muuch C;