# What is the vertex of #f(x)= -x^2 + 6x + 3#?

##### 1 Answer

May 23, 2017

#### Explanation:

Use

In this case,

Then, the coordinate is

Derivation of this formula:

We know the vertex's x position is the average of the two solutions. To find the x component of the vertex, we take the average:

We also know that:

where

So then we can derive that:

Voila.