Respuesta :

semsee45

Answer:

(x + 9)(x - 9)

Step-by-step explanation:

Apply the Difference of Two Squares formula: x² - y² = (x + y)(x - y)

Rewrite 81 at 9²

⇒ x² - 81 = x² - 9² = (x + 9)(x - 9)

fieryanswererft

Answer:

[tex]\left(x+9\right)\left(x-9\right)[/tex]

Step-by-step explanation:

[tex]x^2 - 81[/tex]

factor 81 as 9²

[tex]x^2-9^2[/tex]

using formula: a² -b² = (a+b)(a-b)

[tex]\left(x+9\right)\left(x-9\right)[/tex]