# Math Help - Writing a function in standard form to find the vertex.

1. ## Writing a function in standard form to find the vertex.

$x^2+8x+11$

For standard form I got $(x+4)^2=5$ but I should have got
$(x-4)^2=-5$

according to the vertex formula:

-b/2a

2. Originally Posted by Isimbot
$x^2+8x+11$

For standard form I got $(x+4)^2=5$ but I should have got
$(x-4)^2=-5$ Mr F says: No, see below.

according to the vertex formula:

-b/2a
$y = a(x - h)^2 + k$ has a vertex at x = h. Your vertex formula told you that x = -8/2 = -4 therefore h = -4 which agrees with your earlier (correct) calculation.