# What is the vertex form of #y= x^2 - 3x + 9 #?

##### 1 Answer

Dec 19, 2015

It is a minimum.

#### Explanation:

We're studying a trinomial, and we can tell wether its vertex is a minimum or a maximum only by looking at the sign of the coefficient of

It's pretty visible on the graph that the derivative of this expression will first be negative, then become zero and then only be positive.

graph{x^2 -3x + 9 [-8.93, 11.07, 5.4, 15.4]}