# How do you find the vertex and axis of symmetry of y=x^2+8x-7?

Dec 2, 2015

y = x^2 + 8x - 7

Ans: Vertex (-4, -23)

#### Explanation:

x-coordinate of vertex or axis of symmetry:
$x = \frac{- b}{2 a} = - \frac{9}{2} = - 4$
y-coordinate of vertex:
$y = y \left(- 4\right) = 16 - 32 - 7 = - 23$
graph{x^2 + 8x - 7 [-80, 80, -40, 40]}