Respuesta :

poopypantsp

Answer:

-9 is the answer

Step-by-step explanation:

blakeedwards2019

Answer:

k = -9

Step-by-step explanation:

[tex]x^{2} -9=x^{2} + k\\[/tex]

subtract [tex]x^{2}[/tex] from each side

-9 = k

k = -9