# How do you find the vertex of # y=x^2+10x+21#?

##### 2 Answers

#### Explanation:

Sub

The formula

always the

(-5,-4)

#### Explanation:

You have to use the quadratic formula

which becomes

We know that

So it is the vertex and as

The vertex must be

Plug in

so

so the co-ordiantes of the vertex are (-5,-4)