# How do I use the vertex formula to determine the vertex of the graph for y=x^2+4x+1?

May 3, 2015

$x = m {\left(x - a\right)}^{2} + b$
with vertex $\left(a , b\right)$
$y = {x}^{2} + 4 x + 1$
$y = \left({x}^{2} + 4 x + 4\right) - 4 + 1$
$y = \left(x - \left(- 2\right)\right) + \left(- 3\right)$
Vertex is at $\left(- 2 , - 3\right)$