Respuesta :

Answer:

f(x) =  (x+6)² - 10

Step-by-step explanation:

To write the equation in vertex form we, we need to use completing square method.

f(x) = x²+ 12x + 26 = (x² + 2*x*6 + 6²) - 6² + 26 = (x+6)² -36 + 26 =

= (x+6)² - 10

f(x) =  (x+6)² - 10