# Algebra II

posted by
**Jonathan**
.

Write y=x^2+4x-1 in vertex form.

y=x^2+4x-1

y=(x^2+4x+8)-1-8

y=(x+2)^2-9

This isnt one of my answer choices,what am I doing wrong?

in second line:

y=(x^2+4x** +4 ** )-1 ** +4 **

(take one half of the middle coefficient, then square it)

y=(x^2+4x + 4 )-1 - 4