Respuesta :

Answer:

x is greater than or equal to 6 or

x is less than or equal to -6

Step-by-step explanation:

f(x)= sqrt x^2-36

Plug in 6. for x

Results are sqrt (6)^2-36= sqrt 0 = 0

Plug in -6 for x

Results are (-6)^2-36= sqrt 36-36 = sqrt 0 = 0