Respuesta :

jayster107
x ^2- 4x + 4 = 11 + 4 

( x - 2 ) ² = 15 

x - 2 = ±√15 

x = 2 ±√15

I hope this is right or at least close...;)
use the coefficient of x , divide it by two and square it .
4/2=2
x^2+4x+(4-15)
(x+2)^-15
vertex is (-2,-15)