# What is the axis of symmetry and vertex for the graph y=x^2 +2x -5?

Jul 5, 2017

See explanation.

#### Explanation:

To calculate the vertex of a parabola you use the following formulas:

and

where

## $\Delta = {b}^{2} - 4 a c$

Here we have:

$p = \frac{- 2}{2} = - 1$

$\Delta = {\left(2\right)}^{2} - 4 \cdot 1 \cdot \left(- 5\right) = 4 + 20 = 24$

$q = - \frac{24}{4} = - 6$

The axis of symetry of a parabola is $x = p$. Here it is: $x = - 1$

The vertex is $V = \left(- 1 , - 6\right)$. The axis of symetry: $x = - 1$