Respuesta :
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)
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]