What is the vertex form of -y=x^2+4x+5?

Feb 26, 2016

$y = {\left(x + 2\right)}^{2} - 1.$

Explanation:

$y = - {x}^{2} - 4 x - 5$
x-coordinate of vertex:
$x = - \frac{b}{2 a} = \frac{4}{- 2} = - 2$
y-coordinate of vertex:
y(-2) = - 4 + 8 - 5 = -1
Vertex form: $y = {\left(x + 2\right)}^{2} - 1$
graph{- x^2 - 4x - 5 [-10, 10, -5, 5]}