## anonymous 5 years ago f(x)=x^2+4x+1, identify the vertex and axis of symmetry.

1. anonymous

complete the square to get $f(x)=(x+2)^2+1-4=(x+2)^2-3$

2. anonymous

vertex is (-2,-3) and axis of symmetry is x=-2

3. anonymous

or you could just use $-\frac{b}{2a}=-\frac{4}{2}=-2$ and $f(-2)=(-2)^2+4\times -2+1=4-8+1=-3$

4. anonymous

thanks A LOT

5. anonymous

$-\frac{b}{2a}$ is usually easier because you do not have to keep track of adding and subtracting. to find the y coordinate just substitute